Question

10 Find the area of a circle with
A Diameter 21 m B. Radius 7 cm
c. Diameter 7 m D. Radius 20 cm​

Answer 1

Answer:

$(a)d = 21m \\ r = \frac{21m}{2} \\ \pi {r}^{2} = \frac{22}{7} \times \frac{21}{2} \times \frac{21}{2} = 346.5 {m}^{2}$

$(b) \: r = 7cm \\ area = \pi{r}^{2} = \frac{22}{7} \times 7 \times 7 \\ area = 154 {cm}^{2}$

$(c) \: d = 7m \\ r = \frac{7}{2} m \\ area = \pi {r}^{2} = \frac{22}{7} \times \frac{7}{2} \times \frac{7}{2} \\ = \frac{77}{2} = 38.5 {cm}^{2}$

$(d) \: r = 20cm \\ area = \pi {r}^{2} = \frac{22}{7} \times 20 \times 20 \\ = 1257.14 {cm}^{2}$