A circle is inscribed in a rectangular trapezoid from the base of 6 and 7, find S area.

Let’s build the height of the CH trapezoid.

In a right-angled triangle СDН, the length of the segment is DH = AD – AH = AD – BC = 7 – 6 = 1 cm.

Then, by the Pythagorean theorem, CD ^ 2 = CH ^ 2 + DH ^ 2 = AB ^ 2 + 1. (1).

Since a circle is inscribed in the trapezoid, AB + CD = BC + AD = 13.

AB + CD = 13. (2).

Let’s solve the system of equations 1 and 2.

AB = 13 – CD.

CD ^ 2 = (13 – CD) ^ 2 + 1.

CD ^ 2 = 169 – 26 * CD + CD ^ 2 + 1.

26 * CD = 170.

CD = 170/26 = 85/13.

AB = 13 – 85/13 = 84/13 cm.

Determine the area of the trapezoid.

Savsd = (BC + AD) * AB / 2 = 13 * (84/13) / 2 = 42 cm2.

Answer: The area of the trapezoid is 42 cm2.



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