This is one from the IQ tester series. 90 D In A R A means 90 degrees in a right angle. Some others in this series are, 7 C in a R = 7 colors in a rainbow. 5 L from A are V = 5 letters from Alphabets are Vowels. 29 D in F in L Y = 29 Days in Feb is Leap Year. 9 P in SS = 9 planets in the solar system.