One angle is 118°. Find the other angle, x.

Step by step

The question

Question: find x when the angles on a straight line are 118° and x.

1 Use the angle fact

Angles on a straight line add up to 180°.

So we add them all and make it 180: 118 + x = 180.

Is x alone now?

Not yet: + 118 is still with x.

How do we remove it?

2 Remove the 118

We want x by itself.

The 118 is in the way.

To remove 118, we take away 118.

We do it on both sides.

Why both sides?

The = sign means both sides are the same amount.

If we change only one side, they are not the same any more.

118 and − 118 cancel each other.

They make zero.

180 minus 118 is 62.

So x = 62.

The angle x is 62°.

3 Check

Let's check: put x = 62 back and add the angles.

They add up to 180°.

So x = 62 is right!

Let's look back.

First: use the angle fact.

Then: remove the 118.

Last: check.