A trapezoid is a quadrilateral in which one pair of opposite sides is parallel, and the sides are not equal to each other.
The middle line of a trapezoid is a line segment connecting the midpoints of the sides of the trapezoid. It is parallel to the bases, and its length is equal to half the sum of the bases:
m = (a + b) / 2; where:
m is the middle line of the trapezium NK;
a – the smaller base of the BC trapezoid;
b – larger AD base.
HK = (BC + AD) / 2;
(BC + AD) = 2 ∙ HK;
ВС = 2 ∙ НК – АD;
BC = 2 ∙ 28 – 40 = 56 – 40 = 16 cm.
Answer: The length of the smaller base of the trapezoid is 16 cm.
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