tolong jawab memakai caranya :)

[tex](r + r ) ^{2} = {p}^{2} - {d}^{2} \\ (16 + r ) ^{2} = {41}^{2} - {9}^{2} \\ (16 + r ) ^{2} =1681 - 81 \\ (16 + r ) ^{2} =1600 \\ 16 + r = \sqrt{1600} \\ 16 + r = 40 \\ r = 40 - 16 \\ r = 24 \: cm \: (a)[/tex]
Jawabannya A.
Jdikan yg terbaik..Makasih :)