On a piece of paper, use a protractor to construct a triangle with angle measures of 40° and 60º.

what is the measure of the third angle?

60°
80°
100°
180°

Considering that the sum of the measures of the internal angles of a triangle is of 180º, the third angle measures 80º.

A triangle is composed by three internal angles, and the sum of their measures is of 180º.

In this problem:

The first two angles have measures of 40º and 60º.The third angle measures x.

Since the sum of the measures is of 180º:

The third angle measures 80º.

A similar problem is given at link

All 3 triangle angles sum to 180 degrees.
So third angle = 180 -40 -60
third angle = 80 degrees

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Many things that seem threatening in the dark become welcoming when we shine light on them