The measure of a base angle of an isosceles triangle is 20. What is the measure of the vertex?

140 degrees

Step-by-step explanation:

Since this triangle is isosceles, the base angles must be equal. This means that two out of the three angles in the triangle are 20 degrees. Since all of the angles together in a triangle must add up to 180 degrees, the angle of the vertex is 180-20-20=140 degrees. Hope this helps!

140

Step-by-step explanation:

The base angle is 20.  That means the other base angle is also 20

20+20 = 40

The sum of the angles of a triangle is 180

180-40= 140

That means the third angle must be 140

paula, cory, and krista

l.ln.lln.k.nkl

step-by-step explanation: