Question

Please answer Q7 b. It’s very urgent :(

Answer 1

Step-by-step explanation:

I don't know about this question sorry

Answer 2

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Volume of sphere =

Volume of sphere = Volume cone cone 1 + Volume of cone 2

$\frac{4}{3} \pi {r}^{3} = \frac{1}{3} \pi \: {r}^{2} h \: + \frac{1}{3} \pi {r}^{2} h \\ \frac{4}{3} {r}^{3} = \frac{1}{3} {r}^{2} h + \frac{1}{3} {r}^{2} h \\ \frac{4}{3} {r}^{3} = \frac{1}{3} ( {r}^{2} h + {r}^{2} h) \\ 4 {r}^{3} = {r}^{2}h + {r}^{2} h$

$\huge{\underline{Given:}}$

$\longrightarrow$Radius of cone 1 = 3 cm

$\longrightarrow$Height of cone 1 = 5 cm

$\longrightarrow$Radius of cone 2 = 2 cm

$\longrightarrow$Height of cone 2 = 4.5 cm

Substituting values:

$4 {r}^{3} = 3 \times 3 \times 5 + 2 \times 2 \times 4.5 \\ {r}^{3} = \frac{45 + 18}{4} \\ {r}^{3} = \frac{63}{9} \\ {r}^{3} = 7 \: cm \\ r = \sqrt[3]{7} \: \: or \: \: 1.91cm$

Surface area of sphere:

$= 4\pi {r}^{2}$

$= 4 \times \pi \times { \sqrt[3]{7} }^{2} \\ = 4 \times \frac{22}{7} \times 3.64 \\ = 88 \times 0.52 \\ = 45.76\: {cm}^{2}$

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