Net of a square pyramid base 8 cm, slant height 9 cm

Step by step

The question

Question: draw the net of a square pyramid, base 8 cm, slant height 9 cm, and find its surface area.

The surface area is the area of all the outside faces together.

A net shows every face flat.

1 Unfold it

Flat: the square base, with a triangle on each side.

2 Area of each face

The square base: 8 × 8 is 64.

Each triangle: half × 8 × 9 is 36.

Careful!

Count every face in the net.

There are four triangles.

3 Add them all

We add all 5 faces: 208 cm².

4 Check

Let's check another way.

Four triangles of half 8 times 9 are two whole 8 by 9 rectangles: 144.

Plus the base 64.

Together 208.

So the answer is right!

Let's look back.

First: unfold it.

Then: area of each face.

Then: add them all.

Last: check.