Answer:
∠ SQT = 63°
Explanation:
since QS bisects ∠ RQT , then
∠ RQS = ∠ SQT = 7x + 7
then
∠ RQS + ∠ SQT = ∠ RQT , that is
7x + 7 + 7x + 7 = 9x + 54
14x + 14 = 9x + 54 ( subtract 9x from both sides )
5x + 14 = 54 ( subtract 14 from both sides )
5x = 40 ( divide both sides by 5 )
x = 8
Then
∠ SQT = 7x + 7 = 7(8) + 7 = 56 + 7 = 63°