The lenght of a rectangle deck is 4 times its width if the decks perimeter is 30 ft, what is the decks area?

Define x :

Let the width be x.
Width = x
Length = 4x


Find x :

Perimeter = 30 ft
2 (x + 4x) = 30
2(5x) = 30
10x = 30
x = 30 ÷ 10 
x = 3


Find Length and Width :

Width = x = 3
Length = 4x = 4(3) = 12


Find Area :

Area = 3 x 12 = 36 ft²


Answer : Area = 36 ft²