Answer:
7. m∠PQR =70° m∠PQS = 140°
8. m∠CAD = 18° m∠BAD = 72°
9. m∠RST = 22°
Step-by-step explanation:
Question 7
If QR bisects (divides into two equal parts) ∠PQS then:
⇒ m∠PQR = m∠RQS
⇒ 4x - 10 = -3x + 130
⇒ 4x - 10 + 10 = -3x + 130 + 10
⇒ 4x = -3x + 140
⇒ 4x + 3x = -3x + 140 + 3x
⇒ 7x = 140
⇒ 7x ÷ 7 = 140 ÷ 7
⇒ x = 20
Substitute the found value of x into the expression for m∠PQR:
⇒ m∠PQR = 4(20) - 10 = 70°
As QR bisects ∠PQS:
⇒ m∠PQS = 2m∠PQR = 2 × 70° = 140°
Question 8
From inspection of the given diagram, ∠BAC = 90°.
⇒ m∠CAD + m∠BAD = 90
⇒ x + 15 + 5x + 57 = 90
⇒ 6x + 72 = 90
⇒ 6x + 72 - 72 = 90 - 72
⇒ 6x = 18
⇒ 6x ÷6 = 18 ÷ 6
⇒ x = 3
Substitute the found value of x into the expressions for the two angles:
⇒ m∠CAD = 3 + 15 = 18°
⇒ m∠BAD = 5(3) + 57 = 72°
Question 9
From inspection of the given diagram (and assuming R is on the empty line segment):
m∠RSU = m∠RST + m∠TSU
⇒ 91° = m∠RST + 69°
⇒ 91° - 69° = m∠RST + 69° - 69°
⇒ 22° = m∠RST
⇒ m∠RST = 22°
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