Question

what is the value of a? write your answer as an integer or as a decimal rounded to the nearest tenth.

Explanation:

Step1: Use the exterior - angle property of a triangle

The exterior - angle of a triangle is equal to the sum of the two non - adjacent interior angles. So, $6a - 5=(4a - 26)+3a$.

Step2: Simplify the right - hand side of the equation

$(4a - 26)+3a=4a+3a - 26=7a - 26$. So the equation becomes $6a - 5 = 7a - 26$.

Step3: Solve for a

Subtract $6a$ from both sides: $-5=a - 26$. Then add 26 to both sides: $a=-5 + 26$.

Answer:

$a = 21$