Question

if TSA and CSA of cone is 704cm square

and 550 cm square . find radius​

Answer 1

Step-by-step explanation:

Total surface area of cone = 704 cm²

πr(r + l) = 704 cm²

πr² + πrl = 704 ---(1)

And, curved surface area of cone = 550 cm²

2πrl = 550 cm²

πrl = 550/2 ---(2)

Substituting 2 in 1,

$\pi {r}^{2} + \frac{550}{2} = 704 \\ \pi {r}^{2} + 275 = 704 \\ \pi {r}^{2} = 704 - 275 = 429 \\ {r}^{2} = \frac{429}{\pi} = \frac{429}{ \frac{22}{7} } = 429 \times \frac{7}{22} = 136.5 \\ \\ r = \sqrt{136.5} = 11.68$