Question

Lily 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

*the complete diagram is given in the attachment below

Answer:

✔️ 198.7 m²

✔️$219.9

Explanation:

✔️Area around the wall to be painted = area of rectangle - area of triangle

= L×B - ½ab×sin(C)

Where,

L = 17 m

W = 14 m

a = 9.5 m

b = 8.7 m

C = 72°

Plug in the values

Area around the wall to be painted = 17×14 - ½×9.5×8.7×sin(72)

= 238 - 39.3024105

≈ 198.7 m² (nearest tenth)

✔️Cost of painting the wall:

Paint cost $21.99 per container of 20 liters

Find how many liters would be needed if 1 liter covers 1m²

Liters needed to cover 198.7 m² = 198.7*1 = 198.7 liters of paint

20 liters = 1 container,

198.7 liters = 198.7/20 = 9.935 ≈ 10 containers

1 container cost $21.99

10 containers = 21.99×10 = $219.9