Question

the diagram shows a triangle.
what is the value of a?
a = \square°
submit

Explanation:

Step1: Sum triangle angles to 180°

$(7a-14) + 78 + 46 = 180$

Step2: Simplify the left side

$7a + (-14+78+46) = 180$
$7a + 110 = 180$

Step3: Isolate the term with $a$

$7a = 180 - 110$
$7a = 70$

Step4: Solve for $a$

$a = \frac{70}{7}$

Answer:

$10$