A landing pad for a helicopter is in the shape of a circle - Junior Cycle Mathematics - Question 7 - 2016

The perimeter (circumference) of a circle can be calculated using the formula:

$P = 2 \pi r$

Substituting the radius we found in part (a):

$P = 2 \pi (3)$ $P \approx 2 \times 3.14 \times 3 \approx 18.84 \text{ m}$

Rounding to the nearest metre, the perimeter is approximately 19 m.

The area of a circle is calculated using the formula:

$A = \pi r^2$

Using the radius found in part (a):

$A = \pi (3)^2 = 9\pi$ $A \approx 9 \times 3.14 \approx 28.26 \text{ m}^2$

Rounding to one decimal place, the area is approximately 28.3 m².