Answer:
B. -4,-1
Step-by-step explanation:
Answer:
∠ACB = 72
Step-by-step explanation:
OAD is straight line.
∠DAB + ∠OAB = 180
142 + ∠OAB = 180
∠OAB = 180 - 142
∠OAB = 38
ΔAOB is isosceles triangle. OA = OB = radius
∠OAB = ∠OBA = 38 {angles opposite to equal sides or equal}
In ΔAOB ,
∠OAB + ∠OBA + ∠AOB = 180 {Anlge sum property of triangle}
38 + 38 + ∠AOB = 180
76 + ∠AOB = 180
∠AOB = 180 - 76
∠AOB = 104
THe angle subtended by an arc of a circle at the center is double the angle subtended by it at any point on the remaining part of the circle
∠AOB = 2*∠ACB
∠ACB = ∠AOB/2
= 104/2
∠ACB = 72
the equation to solve these problems is:

1)175*85=100x
x=148.75
2)76*100=80x
x=95
3) 96*100=160x
x=60
4)85*120=100x
x=102
5)56*100=75x
x=74.66
The student made a mistake in Line 1: AC=2, DF=2 AC ≅ DF .