To find the surface area of any object, the first step that you must do is find all shapes that are present in the object.
Here we have 2 triangles and 3 rectangles.
Knowing this, simply find the area of each shape.
Since the triangles are the same, one is facing up and the other down, they both would be 15.6 cm^2.
The rectangles would be 54 cm^2. as there are 3 ( 6 x 3 cm) ones.
Add the values up to have the surface area.
It’s 85.2 cm^2.
Down on the bottom, under the fraction line.
Answer:
P=2(l+w)
divide the both sides by 2
P/2 = l +w
make w the subject of the formula
P/2 - l =w
w = P/2 - l