Final answer:
The formula for the area of a circle is A = πr², with A representing area, π (pi) being a constant, and r the radius of the circle. The area is measured in square meters (m²), and when calculating, we use the measured radius to produce an area with the same number of significant figures.
Step-by-step explanation:
The formula for the area of a circle is represented by A = πr², where A stands for area, π (pi) is a constant approximately equal to 3.14159, and r represents the radius of the circle. The SI unit for measuring area is the square meter (m²). Thus, when calculating the area of a circle with a given radius, we square the radius (multiply it by itself) and then multiply the result by π. If the radius is measured in meters, the resulting area will be in square meters.
For example, if a circle has a radius of 1.2 meters, we calculate the area by plugging the radius into the area formula as follows: A = πr² = (3.1415927...)×(1.2 m)² = 4.5238934 m². However, since the radius has only two significant figures, the result should also be reported with two significant figures, making the approximate area A=4.5 m².