The equation is given to compute A(7) = A(r) pi r²
7 = pi r²
r² = 7/pi
value of pi = 3.14
so,
r² = 7/3.14
r = √ (7/3.14)
r = 1.49
5+10=15
or 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1
I am pretty sure the answer is,
B
Answer
Sol: The correct answer is b. three planes that contain point B are ABD, AEF and DHF.