If the degree measures of the angles of quadrilateral are 4x, 7x, 9x and 10x, what is the sum of the measures of the smallest angle and largest angle?
Given,
ABCD is a parallelogram,
Angles of quadrilateral 4x , 7x , 9x , 10x
= 4x+7x+9x+10x = 360° [ angle sum property of quadrilateral]
= 30x = 360°
= 
Hence, sum of smallest and largest angles = 4x+10x = 4×12+10×12
= 48°+120° = 168°
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