Melanie’s bedroom walls are 45% painted. the area of her walls totals 420 square feet. What is the number of square feet of Melanie’s walls that still need to be painted? 

Melanie’s bedroom walls are 45% painted. the area of her walls totals 420 square feet. What is the number of square feet of Melanie’s walls that still need to be painted?

Melanie's walls still need 231 square feet to be painted.

To find out how much of Melanie's bedroom walls still need to be painted, we need to calculate the remaining percentage of the walls that need to be painted and then determine the corresponding area in square feet.

If 45% of the walls are already painted, then 100% - 45% = 55% of the walls still need to be painted.

To find the area of the walls that still need to be painted, we can calculate 55% of the total wall area:

55% of 420 square feet = 0.55 * 420 square feet

Let's compute that:

0.55 * 420 = 231 square feet

So, Melanie's walls still need 231 square feet to be painted.

Area and Perimeter of a Square

The area and perimeter of a square can be calculated using the following formulas:

Area of a square: Area = side length * side length
Perimeter of a square: Perimeter = 4 * side length

In both formulas, "side length" refers to the length of one side of the square.