Question

the diagram shows a triangle.
what is the value of t?
write your answer as an integer or as a decimal rounded to the nearest tenth.
t = \boxed{}

Explanation:

Step1: Sum angles to 180°

$(2t+20) + (12t+20) + 31 = 180$

Step2: Combine like terms

$14t + 71 = 180$

Step3: Isolate term with t

$14t = 180 - 71$
$14t = 109$

Step4: Solve for t

$t = \frac{109}{14}$

Answer:

$7.8$