please ya dijawab, makasih

[tex]keliling \: alas \: = \pi \times d \\ 88 = \frac{22}{7} \times d \\ d = 28 \: cm \\ r = \frac{28}{2} = 14 \: cm \\ t = \sqrt{ {20}^{2} - {14}^{2} } \\ t = \sqrt{400 - 196} \\ t = \sqrt{204} \\ t = 2 \sqrt{51 \: } (b)[/tex]

Maaf kalo salah, semoga membantu