Question

1. A rectangle has a length of 5cm and a height of 4cm.

a. Find the area of the rectangle

b. Find the perimeter of the rectangle.

c. A scale factor of .5 is used to reduce the rectangle. What is the new area?

d. A scaled factor of 2 is used to increase the triangle. What is the new area?

Answer 1

1. 20 cm²
2. 18 cm
3. 5 cm²
4. 80 cm²

Explanation:

Q1(a)

• Area = length x height
• Area = 5 x 4
• Area = 20 cm²

Q1(b)

• Perimeter = 2(length + height)
• Perimeter = 2(5 + 4) = 2(9)
• Perimeter = 18 cm

Q1(c)

• New dimensions are : 5/2 = 2.5 and 4/2 = 2
• New Area = 2.5 x 2
• New Area = 5 cm²

Q1(d)

• New dimensions are : 2 x 5 = 10 and 2 x 4 = 8
• New Area = 10 x 8
• New Area = 80 cm²

Answer 2

a

20cm squared

b

18cm

c

5cm

d

80cm

Explanation:

a

Area is height multiplied by length in a regular quadrilateral

b

Perimeter is calculated by adding all the sides together

c

0.5 is effectively halving, so instead of 4 multiplied by 5 it is 2 multiplied by 2.5

d

2 is effectively doubling, so instead of 4 multiplied by 5 it is 8 multiplied by 10