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

Answer:

The surface area of door is 33 680 cm².

Step-by-step explanation:

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

$s.a = 2(l \times w) + 2(l \times h) + 2(w \times h)$

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

$s.a = 2(80 \times 3) + 2(80 \times 200) + 2(3 \times 200)$

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

$s.a = 480 + 32000 + 1200$

$s.a = 33680 \: {cm}^{2}$