Given ratio of angles of quadrilateral ABCD is 2:3:5:8
Let the angles of quadrilateral ABCD be 2x,3x,5x,8x, respectively.
We know, by angle sum property, the sum of angles of a quadrilateral is 360o.
⇒2x+3x+5x+8x=360o
⇒18x=360o
∴x=20o.
∴∠A=2x=2×20o=40o,
∠B=3x=3×20o=60o,
∠C=5x=5×20o=100o
and ∠D=8x=8×20o=160o.
∴ The smallest angle =40o.