In triangle ABC, angle C = 90 degrees. BC = 10 tgB = √5: 2. find AB.

The tangent of the angle is the ratio of the opposite leg to the adjacent one, then:

AC / BC = tgABC = √5 / 2 = AC / 10.

AC = (√5 / 2) * 10 = 5 * √5 cm.

From the right-angled triangle ABC, by the Pythagorean theorem, we determine the length of the hypotenuse AB.

AB ^ 2 = BC ^ 2 + AC ^ 2 = 10 ^ 2 + (5 * √5) ^ 2 = 100 + 125 = 225.

AB = √225 = 15 cm.

Answer: The length of side AB is 15 cm.



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