Question

Stephanie just redecorated her bedroom. She wants to paint but needa to know the surface area of the door to see if she has enough?​

Answer 1

The surface area of door is 33 680 cm².

Explanation:

Given that the surface area of a cuboid which is the 3D of rectangle is :

`s.a = 2(l * w) + 2(l * h) + 2(w * h)`

`let \: l = 80 \\ let \: w = 3 \\ let \: h = 200`

`s.a = 2(80 * 3) + 2(80 * 200) + 2(3 * 200)`

`s.a = 2(240) + 2(16000) + 2(600)`

`s.a = 480 + 32000 + 1200`

`s.a = 33680 \: {cm}^(2)`