Sector area

A slice is a fraction of the whole circle, and the angle says which fraction. A full turn is 360°, so 45° is 45 out of 360 — that is 1/8 of the circle.

Now the whole circle. Its area is π × r × r : 3.14 × 6 × 6 = 113.04.

Then take the slice's share of it: 1/8 of 113.04 is 14.13.

So the area of the slice is 14.13 cm².