The side of the rhombus is 41 cm, and one of its diagonals is 18 cm. Find the second diagonal.

The diagonals of the rhombus, at the point of their intersection, are halved and intersect at right angles.

Then AO = OC = AC / 2, ВO = DO = ВD / 2 = 18/2 = 9 cm, and triangle AOB is rectangular.

In a right-angled triangle AOB, according to the Pythagorean theorem, we determine the length of the leg AO.

AO ^ 2 = AB ^ 2 – OB ^ 2 = 1681 – 81 = 1600.

AO = 40 cm.

Then AC = 2 * AO = 2 * 40 = 80 cm.

Answer: The length of the second diagonal is 80 cm.



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