Final answer:
In JavaScript, the function calculateCircleArea calculates the area of a circle using the formula A = πr². It returns the area with two significant figures if the radius is provided with two significant figures. The precision of the output can be adjusted based on the required accuracy.
Step-by-step explanation:
To calculate the area of a circle in JavaScript, we can create a function called calculateCircleArea which takes the radius of a circle as an argument and then uses the formula A = πr², where π (pi) approximates to 3.14159 and 'r' is the radius of the circle.
This formula was known to the ancient Greeks and continues to be the standard for calculating circle areas. The function returns the calculated area, keeping in mind that if the radius has only two significant figures, the result should be represented with two significant figures as well to reflect the precision of the input data.
Here is an example of the function in JavaScript:
function calculateCircleArea(r) {
const pi = 3.14159;
return parseFloat((pi * r * r).toFixed(2));
}
When you input a radius value of 1.2 meters, the function will calculate the area and then output it with two significant figures, giving us 4.5 m² as the result.
Remember, the precision of our result is governed by the precision of the radius provided. If a higher accuracy is required, for instance, if using a calculator with eight-digit output, we can adjust the function to reflect this greater degree of precision.