If the angles of a quadrilateral are in the ratio 3:5:9:13, then find the measure of the smallest angle.
Given,
Ratio of angles of quadrilateral = 3:5:9:13
Let sides are = 3x ,5x ,9x, 13x
= 3x+5x+9x+13x = 360° (angle sum property of quadrilateral)
= 30x = 360°
= x = 
So, length of smallest angle = 3x = 3×12 =36°
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