Question

which of the following is the correct formula to calculate the area (a) of a rectangle with length (l) and width (w)?
a = 2l + 2w
a = (1/2)lw
a = l + w
a = lw
which expression correctly represents the area a of a circle with a radius r?
a = wr
a = (1/2)wr^2
a = (2w)r
a = wr^2
what is the correct formula for the area a of a triangle with base b and height h?
a = (1/2)bh
a = bh
a = b + h
a = 2b + h

Explanation:

Step1: Recall the formula for the area of a rectangle

The area of a rectangle is calculated by multiplying its length and width. So \(A = lw\).

Step2: Recall the formula for the area of a circle

The formula for the area of a circle is \(A=\pi r^{2}\).

Step3: Recall the formula for the area of a triangle

The area of a triangle is given by \(A=\frac{1}{2}bh\) (where \(b\) is the base and \(h\) is the height).

Answer:

For the rectangle: \(A = lw\) (the fourth option in the first question).
For the circle: \(A=\pi r^{2}\) (the fourth option in the second question).
For the triangle: \(A=\frac{1}{2}bh\) (the first option in the third question).