Question

what is the value of y? y + 42° y - 39° y y = °

Explanation:

Step1: Apply exterior - angle property

The exterior - angle of a triangle is equal to the sum of the two non - adjacent interior angles. So, $y + 42=(y - 39)+y$.

Step2: Simplify the equation

Expand the right - hand side: $y + 42=y - 39+y$. Combine like terms: $y+42 = 2y-39$.

Step3: Solve for y

Subtract y from both sides: $42=2y - y-39$. Then $42=y - 39$. Add 39 to both sides: $y=42 + 39$.

Answer:

$y = 81$