Rhombus ABCD has perimeter 148, and one of its diagonals has length 20. How long is the other diagonal?
+526 Perimeter of rhombus = 4 × side = 148 A B
⇒ side = 37
Consider rhombus ABCD O
AB = BC = CD = DA & AC ⊥ BD
AC & BD intersect at O. D C
BD = 20 so, OB = OD = 10
Since ∠COD = 90 [diagonals of rhombus intersect at right angles]
⇒ OC = 35.6
Diagonal AC = 71.2 units
