The time it takes to drive between two cities is inversely proportional to the average speed of a car. It took Akiko 1.4 hours to drive from New Britain to Lakeview at an average speed
of 40 miles per hour (mph). How long will it take Akiko to drive from New Britain to
Lakeview at an average speed of 50 mph? Describe how to solve this problem using
complete sentences.

Since we are given the perimeter, we add the lengths of the sides and set the sum equal to the perimeter. Then we solve for x.

3x + 3x - 1 + 4x + 1 = 70

10x = 70

x = 7

Now we pick two sides that can be used as a base and a height to calculate the area. In a right triangle, the legs form a right angle, and can be used as base and height.

base = 3x = 3(7) = 21

height = 3x - 1 = 3(7) - 1 = 21 - 1 = 20

area = base * height/2

area = (21)(20)/2 = 21 * 10 = 210

210