Question

what is the value of y?
triangle with angles 39°, 3y - 34°, and an exterior angle y + 48°
write your answer as an integer or as a decimal rounded to the nearest tenth.
y =
submit

Explanation:

Step1: Use exterior angle theorem

The exterior angle of a triangle equals the sum of the two non-adjacent interior angles, so:
$y + 48 = 39 + 3y - 34$

Step2: Simplify the right-hand side

Combine like terms on the right:
$y + 48 = 3y + 5$

Step3: Isolate y terms

Subtract $y$ from both sides:
$48 = 2y + 5$

Step4: Isolate the constant term

Subtract 5 from both sides:
$43 = 2y$

Step5: Solve for y

Divide both sides by 2:
$y = \frac{43}{2}$

Answer:

$21.5$