In an isosceles trapezoid with a lateral side of 10 cm, a large base of 17 cm, a height of 8 cm. find a smaller base.

Draw two heights of the trapezoid from obtuse angles.

In a right-angled triangle ABH, we define, according to the Pythagorean theorem, the length of the leg AK.

AK ^ 2 = AB ^ 2 – ВK ^ 2 = 100 – 64 = 36.

AK = 6 cm.

Triangles ABK and CDH are equal, since the angle BAK = CDH, since these are the angles at the base of an isosceles trapezoid, AB = CD as lateral sides, then DH = AK = 6 cm.

Segment КН = АD – AK – DH = 17 – 6 – 6 = 5 cm.

Since BK and CH are heights, then BCHK is a rectangle, then BC = KH = 5 cm.

Answer: The smaller base is 5 cm.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.