help me with this please

Question

Select the correct answer.

Points A and B lie on a circle centered at point O. If OA = 5 and  what is the area of sector AOB? Use the value π = 3.14, and choose the closest answer.

A. 

19.6 square units

B. 

39.3 square units

C. 

7.85 square units

D. 

15.7 square units

Answer 1

length of arc (AB) = area of sector AOB

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circumference area of circle

OA is the radius of the circle

area of circle = PI * Radius ^ 2 = 78.5

1 = area of sector AOB

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4 78.5

area of sector AOB = 78.5/4 = 19.625 (A)

Answer 2

Area of sector AOB = (1/4) π*25 = 19⁺, i.e. the answer is A.