90 D In A R A answer?

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.