Question

Please help me. Noura is redecorating her house. She needs to work out the area of the wall around her triangular window in order

to find out how much paint she
needs.

a) Calculate the area of the wall
she needs to paint, to a suitable level
of accuracy, explain your answer.
b) Paint is sold in 20 litres containers,
costing $21.99 per container. Use
your answer from part (a) to
calculate and explain how much it
will cost to paint the wall. Assume 1
litre of paint covers 1m2 *​

Answer 1

a. 277.3 m²

b. $307.86

Explanation:

a. Area of the wall to be painted = area of rectangle - area of triangle

= L × W + ½×a×b×sin θ

L = 17 m

W = 14 m

a = 8.7 m

b = 9.5 m

θ = 72°

Plug in the values into the equation

Area of the wall = (17×14) + (½*8.7×9.5×sin 72)

Area of the wall = 238 + 39.3024105

Area of the wall to paint ≈ 277.3 m²

b. 20 liters of paint of 1 container cost $21.99

If 1 liter of paint covers 1m², therefore,

277.3 m² will need = 277.3 × 1 = 277.3 liters of paint.

20 liters = 1 container of paint

277.3 liters = 277.3/20 = 13.865 ≈ 14 containers

1 container = $21.99

14 containers = 21.99 × 14 = $307.86