Textbook: 1.3 Page 33 - Question #9

9) Examine the bookshelf. It is constructed of thin hardwood. The top, bottom and all three shelves are the same size. There is an equal distance between the top, the shelves and the base. 

a) What is the surface area of one shelf? Include both sides, but ignore the edges. 

b) What is the total surface area of the bookcase?

c) What is the fewest number of surfaces for which you need to find the surfaces area in order to answer part b)?

Only three surface areas need to be calculated. (back, shelf, side)

Test: Rational World Problem Question #4

4. The figure below is composed of seven congruent squares. The area is 43.75 cm². Calculate its perimeter. 

A = area 
P = perimeter  
A = 43.75 cm 
 7 congruent squares 
14 congruent squares = P 

First divide the area of the shape by the number of congruent squares to get the area of one  square.

Find the square root of the area of one square to get the side length. 

Multiply the side length of one square by the number of sides to get the perimeter. 

Algebraic Way 

The perimeter of the shape is 35 cm.

Textbook: Chapter 2.4 Page 80 Question #26

26. A bag of fertilizer will cover an area of 200m² . Determine the dimensions of a square that 3/4 of a bag of fertilizer will cover. Express your answer to the nearest tenth of a metre.

 

So, the dimensions of a square that 3/4 of a bag of fertilizer will cover are 12.2m by 12.2m. 

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Textbook: Chapter 2.2 Page 62 Question #27

27. The mean of six rational numbers is -4.3.

     a) What is the sum of the rational numbers?   

      b) If five of the numbers each equal -4.5, what is the sixth number?  

a)  -4.3 x 6 = -25.8 

b) You multiply -4.5 by 5 to get the sum of the first 5 numbers.

 -4.5 x 5 = -22.5a

Then you subtract -22.5 from -25.8 

-25.8 - (-22.5) = -3.3 

So, the sixth number is -3.3

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