The height AD of triangle ABC divides the side BC into segments BD and CD

The height AD of triangle ABC divides the side BC into segments BD and CD so that BD equals 15 cm; СD equals 5 cm Find the side АС if the angle B is 30 degrees.

Since AD is the height of triangle ABC, triangles ABD and ACD are rectangular.

In a right-angled triangle ABD through leg BD and angle ABD we determine the length of leg AD.

tgАВД = АD / ВD.

АD = ВD * tgАВD = 15 * (1 / √3) = 15 * √3 / 3 = 5 * √3 cm.

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

AC ^ 2 = AD ^ 2 + CD ^ 2 = (5 * √3) ^ 2 + 5 ^ 2 = 75 + 25 = 100.

AC = 10 cm.

Answer: The length of the speaker side is 10 cm.



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