Question

what is the value of c? c - 39° c + 49° c =

Explanation:

Step1: Apply exterior - angle theorem

The exterior - angle of a triangle is equal to the sum of the two non - adjacent interior angles. So, $c + 49^{\circ}=c+(c - 39^{\circ})$.

Step2: Simplify the equation

$c + 49^{\circ}=c + c-39^{\circ}$.
$c + 49^{\circ}=2c-39^{\circ}$.

Step3: Solve for c

Add $39^{\circ}$ to both sides: $c+49^{\circ}+39^{\circ}=2c-39^{\circ}+39^{\circ}$, which gives $c + 88^{\circ}=2c$.
Subtract $c$ from both sides: $c - c+88^{\circ}=2c - c$.

Answer:

$c = 88^{\circ}$