Angle at the center x, angle at the edge 35

Step by step

The question

Question: find x.

The angle at the center is x.

The angle at the edge is 35°.

1 Use the circle rule

O is the center of the circle.

Lines from A and B to the center make the angle at the center.

Lines from A and B to C, on the edge, make the angle at the edge.

Both angles stand on the same arc: the orange part of the circle, from A to B.

Circle rule: the angle at the center is double the angle at the edge.

This is always true.

So x is double 35: x = 2 × 35.

2 times 35 is 70.

So x = 70.

2 Check

Let's check: double 35°.

70° is double 35°.

So x = 70 is right!

Let's look back.

First: use the circle rule.

Last: check.