The area of a circular sector of central angle α (in radians) in a circle of radius r is given by
... A = (1/2)r²×(α - sin(α))
Your area is expected to be computed as the sum of the areas of a sector with angle π/3 in a circle of radius 8 and a sector with angle π/2 in a circle of radius 6.
... A = (1/2)8²×(π/3 - sin(π/3)) + (1/2)6²×(π/2 - sin(π/2))
... A ≈ 16.07
Radii are in inches so the units of area will be in². The appropriate choice is
... 16.10 in²
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It should be noted that the geometry described is impossible. Chord CD of circle A will have length 6√2 ≈ 8.4853 inches. Chord CD of circle B will have length 8 inches. They cannot both be the same chord.
The annual interest rate is 3.5%.
Solution:
Given Interest (I) = $26.25
Principal (P) = $500
Time (t) = 18 months
Rate of interest (r) = ?
Time must be in years to find the rate per annum.
1 year = 12 months
Divide the time by 12.
Time (t) = 
years
Now, find the rate of interest using simple interest formula.
<u>Simple interest formula:</u>
⇒ r = 3.5%
Hence the annual interest rate is 3.5%.
