Alana's house sits on a rectangular lot with dimensions 62.4 feet by 108.6 feet. Use mental math to find the perimeter

62.4 + 108.6 = 171

171*2 = (170+1) * 2=340+2=342

Perimeter = 342 feet

The perimeter of a figure is defined by length of its 2D shape.

For a rectangle it is the sum of the length of all its sides

P = a1 + a2 + b1 + b2

Since a rectangle has two sides with the same lengths as the other two

a1 = a2; b1 = b2

P = 2 (a1 + b2)