Question

The measures of the base angles of an isosceles triangle are 3x 5 and 5x - 25. The measure of the vertex angle is 6x - 10. Find the measure of the vertex angle.

Answer 1

Answer: The measure of the vertex angle = 80°

Step-by-step explanation:

Angle sum property of triangle : The sum of the measures of the angles for any triangle is 180 degrees.

So,

$3x+ 5 + 5x-25+6x-10= 180\\\\\Rightarrow\ 14x-30=180\\\\\Rightarrow\ 14x= 210\\\\\Rightarrow x=\dfrac{210}{14}=15$'

Then, vertex angle = $6(15)-10=90-10= 80$

Hence, The measure of the vertex angle = 80°