Question

A rectangle with perimeter 30 in. has length 10 in. What is the area of the rectangle?

Answer 1

Length of rectangle = 10in.

Breadth " " =x

Perimeter= 2( l+b)=30in.

Perimeter=2(10+b)=30in.

=(10+b)=30/2=15

=b=15-10

Breadth=5in.

Answer 2

Answer: 50 in²

Explanation: Remember that the formula for the area of a rectangle is length · width so we need to find the width of the rectangle.

To find the width of the rectangle, let's use our formula

for the perimeter of a rectangle which is 2l + 2w.

Since we know that the perimeter of the rectangle is 30 inches and the length of the rectangle is 10 inches, we have 30 = 2(10) + 2w.

Simplifying on the right side gives us 30 = 20 + 2w.

Now subtract 20 from both sides to get 10 = 2w.

Finally, dividing both sides by 2, we find that 5 = w.

So the width of the rectangle is 5 inches and remember

that the length of the rectangle is 10 inches.

So the area of the rectangle, l · w, is 10 · 5 or 50 in².