Westridge Middle School

Westfir, Oregon

Teacher: Cathy Spencer

Grade 7

 

 

 

This is a variety of problems written by the Algebra 1 class of our middle school.

 

#1  (by:  Allie, Chelsea, Vanessa, Kirsti)

 

For grades 6-8, Ratios

Standard:  Algebra

*Understand patterns and relations.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

The problem:

Allie’s shadow-

         

The shadow of the pole is 11 yards 16 inches. Chelsea’s shadow is 2 meters 8 inches, but Chelsea’s real height is yard meter 24 inches. What is the real height of the pole?

         

How to work the problem:

1.  Find the length of Chelsea’s shadow in inches.  2.   Find the length of Chelsea in inches. 3.  Divide Chelsea’s height by her shadow’s length.

4.  Find the length of the pole’s shadow in inches. 5.  Multiply the answer to Chelsea’s height¸Chelsea’s shadow by the pole height.

 

Answer»8 yards 32 inches (Or 8 yards, 2 feet, 8 inches)

 

 

 

 

#2  Vanessa’s triangle-

 

For grades 5-7, Geometry

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

         

The Problem:  Triangle ABC is a Right Triangle.  Side A is 6 meters long, side B is 8 meters long. Find the length of side C.

How to work the problem: a2+b2=c2      62+82=C2   36+64=100

Answer: c=10 meters

 

 

 


 

#3.  Kirsti’s locker-

 

For grade 7-8, Volume of Rectangle prism and sphere

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

         

 

The Problem:  The top section of the locker is 10 inches wide, 11 inches tall, and 11 inches deep. The lower section is 1 meter 19 inches tall. If you put a small ball in it with a radius of 2 inches, how much space will be left in the locker?

Hint: The equation for the volume of a sphere is V=4/3pr3

How to work the problem: Find the volume of the locker, then find the volume of the sphere. Subtract the volume of the sphere from the volume of the locker.

Answer»7579inches3


#4.  Chelsea Tires-

 

For grades 5-7, Area of a Circle

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

 

The Problem:  The diameter of one tire is 25 inches. There are 10 tires. Find the total area of all 10 tires.

How to work the problem: Find the area of one tire by dividing 25 by 2 to find the radius, then do the equation pr2. Multiply that number by ten to find the area of all ten.

Answer»491 inches2


 

#5  Micheal’s Jungle Gym

 

For grades 5-7, Area of a Circle

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

 

 

The Problem:  This is the jungle gym at our middle school. Many kids play on this. But we wanted to know; what would be the circumference of the two half circles, if you put them together to make a circle. We took the measurement of the height of the jungle gym; which is 6 ft 1 in. What is the circumference in inches? What is the area in inches?

 

A way to solve the problem:

6 ft 1 in = 73 in.                        Convert to common units

R = 73                                      Identify the information you will need

D = 146

3.14 x 146 =458.44 in.               Use the formula Circumference=Diam.X Pi

73 x 73 =5329                           Use the formula Area= PiXradiusXradius

3.14 x 5329 = 160633.06

 

Solution:

A = 160633.06 in2

C = 458.44 in.

 

 

 

#6  Michael’s Rim Problem

 

For grades 5-7, Area of a Circle

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

The Problem:  These rims are “Bling Bling.” With a diameter of 19 inches, what would be the circumference of the rims. What would be the area of the rims?   What would be the radius of the rims?

 

A way to solve it:

3.14 x 19 = 58.66 in         Use the formula circumference=Pi X Diameter

R = 19/2                         Use the formula Radius= ˝ Diameter

9 ˝ x 9 ˝ =58.25           

58.25 x 3.14                    Use the formula Area = Pi X Radius X Radius

 

Solutions:

Circumference = 58.66 in

Area = 182.9050  in2 

Area Rounded to nearest hundredths:182. 91 in2

Radius:  9 ˝ Inches

 

#7 Cassie’s Swings

 

For grades 4th – 7th grades, Number and Operations

Standard:  Number and operations

*Understand numbers

*Understand meanings of operations and how they relate to one another

*Compute fluently and make reasonable estimate

Standard:  Algebra

*Use mathematical models to represent and understand quantitative relationships

 

The Problem:  Swingset: this is a swing set that needs new swings!!! It is from Westridge School.  They took our swings away!

 

It costs $3.75 for 3 feet of wood, finished. Iit costs $5.00 for 10  feet of chain. So if each swing needs 10 feet of chain on each side and 1 foot of wood. 8 swings cost $90.

#1How much does 5 swings cost?

#2 How many full swings can you get with $16.50?

 

A way to solve it:   One foot of wood:  $3.75 divided by 3; 

Chain:  $5.00 X 2;   Compute the cost of 1 swing by adding the two answers.  Multiply by 5. Divide the cost of one swing into $16.50, disregarding the “remainder” since we don’t need partial swings.

Answer: #1. $56.25  for 5 swings

              #2. One swing  can be purchased for $16.50.


#8  John’s tree

For grades 7 or 8, Area of a Cone

Standard:  Geometry

*Analyze characteristics and properties of two and three dimensional geometric shapes.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

 

The Problem:  A logger is wondering how much wood there will be from a trunk tree that has a diameter of 3ft and a height of 54ft. The trunk is roughly a circle that gets gradually smaller until it ends in a tip at the top. 

 

 A way to solve the problem:   To solve this problem you need the formula you use to find the volume of a cone.  First find the area of the circle formed at the base of the tree:  Area= Pi X Radius X Radius.  Multiply by the height of the tree.  Divide that number by three.

 

Solution:   The Volume of wood in the trunk is 127.17 cubic feet

 

 

 

 

#9. Thirsty Kailee

 

For grades 7-8, Rate

Standard:  Algebra

*Understand patterns and relations.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

 

 

The Problem:  n milliliters of water comes out of a drinking fountain per second. If 5n+63=168,  then how many milliliters of water is dispersed per second?

 

A way to solve the problem:

To solve this problem you must get the n alone. Do this by subtracting 63 from both sides, then divide to get rid of the 5.

 

5n+63=168

    -63   -63

___________

    5n=105

  ___  ___

    n  = 21

 

The Solution:  21 milliliters of water comes out of the drinking fountain per second.


#10.  Morgan Wants In

 

For grades 4-6, Area of a Rectangle

Standard:  Algebra

*Understand patterns and relations.

Standard:  Problem Solving

*Build new mathematical knowledge through problem solving

*Solve problems that arise in mathematics and other contexts

*Apply and adapt a variety of appropriate strategies to solve problems.

 

 

The Problem:  We hate the color of this door!  How much paper will it take to cover it up with a great door sign?  The door is 3 feet wide and 6 feet high.

 

A Way to solve this problem:  Find the area of the door using the equation a=bh. . What you do is you put in 3 for b (base) and 6 for h (height).   It looks like this a=3(6).

 

The solution:  18 sq feet.