The length of a rectangle is three times its width and length of its diagonal is 6√(10)cm.What is the perimeter?
L = 3 W
d = sqroot ( L ^ 2 + W ^ 2 )
d = sqroot [ ( 3 W ) ^ 2 + W ^ 2 ] =
sqroot ( 9 W ^ 2 + W ^ 2 ) =
sqroot ( 10 W ^ 2 ) = 6 * sqroot ( 10 )
sqroot ( 10 ) * W = 6 * sqroot ( 10 ) Divide both sides by sqroot ( 10 )
W = 6 cm
L = 3 W = 3 * 6 = 18 cm
P = 2 L + 2 W = 2 ( L + W ) = 2 * ( 18 + 6 ) = 2 * 24 = 48 cm