Two sides of this triangle are congruent.
They are marked with two little marks on each.
The opposite angles are also congruent.
Set their measures equal.
5x = 2x + 30
3x = 30
x = 10
Since x is 10, now we can find the measures of the two unknown angles.
5x = 5 * 10 = 50
The left angle measures 50 deg.
2x + 30 = 2 * 10 + 30 = 20 + 30 = 50
The measure of the right angle is 50 deg.
Since the two bottom angles come out congruent, both measuring 50 deg, it seems the answer is correct.
We can do one more check. The sum of the measures of the angles of a triangle is 180 deg.
Now we add the three measures we have.
50 + 50 + 80 = 180
Yes, the measure we have do add to 180, which proves our answer is correct.
Answer: x = 10; the two bottom angles measure 50 deg.
