Arc length and sector area

A slice is a fraction of the whole circle, and the angle says which fraction. A full turn is 360°, so 270° is 270 out of 360 — that is 3/4 of the circle.

Now the whole circle. Its area is π × r × r : 3.14 × 8 × 8 = 200.96.

Then take the slice's share of it: 3/4 of 200.96 is 150.72.

So the area of the slice is 150.72 cm².