Question

1. calculate the area of the following circles using the radius given each time. (4 marks)

a) radius= 3m
b) radius = 2.7m
c) radius = 10.4cm
d) radius = 9.9mm

Explanation:

Step1: Recall circle area formula

The area of a circle is $A = \pi r^2$, where $r$ is radius, $\pi \approx 3.1416$.

Step2: Calculate area for a)

Substitute $r=3\ \text{m}$:
$A = \pi \times (3)^2 = 9\pi \approx 28.27\ \text{m}^2$

Step3: Calculate area for b)

Substitute $r=2.7\ \text{m}$:
$A = \pi \times (2.7)^2 = 7.29\pi \approx 22.90\ \text{m}^2$

Step4: Calculate area for c)

Substitute $r=10.4\ \text{cm}$:
$A = \pi \times (10.4)^2 = 108.16\pi \approx 339.8\ \text{cm}^2$

Step5: Calculate area for d)

Substitute $r=9.9\ \text{mm}$:
$A = \pi \times (9.9)^2 = 98.01\pi \approx 307.9\ \text{mm}^2$

Answer:

a) $\approx 28.27\ \text{m}^2$
b) $\approx 22.90\ \text{m}^2$
c) $\approx 339.8\ \text{cm}^2$
d) $\approx 307.9\ \text{mm}^2$