Answer:
d ≈ 5.66
Explanation:
given that F varies inversely with d squared, then the equation connecting them is
F =
← k is the constant of variation
to find k use the condition when F = 8, d = 6
k = Fd² = 8 × 36 = 288, hence
F =
when F = 9, then
9 =
← multiply both sides by d²
9d² = 288 ( divide both sides by 9 )
d² = 32 ( take the square root of both sides )
d = ±
, hence
d ≈ 5.66 ← positive value only