In triangle ABC, the heights AA1 and CC1 intersect at point H. Find the height drawn to the side
June 10, 2021 | education
| In triangle ABC, the heights AA1 and CC1 intersect at point H. Find the height drawn to the side of AC if HA1 = 3cm. BA1 = 4cm. AH = 4cm
Consider a right-angled triangle ВНА1, in which, according to the Pythagorean theorem, we determine the length of the hypotenuse ВН.
BH ^ 2 = BA1 ^ 2 + HA1 ^ 2 = 4 ^ 2 + 3 ^ 2 = 16 + 9 = 25.
BH = 5 cm.
Let us prove the similarity of triangles ВНА1 and АНВ1.
Both triangles are rectangular. Angle АНВ1 = ВНА1 as vertical angles. Then right-angled triangles are similar in acute angle.
Then B1H / A1H = AH / BH.
B1H / 3 = 4/5.
B1H = 3 * 4/5 = 12/5 = 2.4 cm.
Then BB1 = BH + B1H = 5 + 2.4 cm = 7.4 cm.
Answer: The length of the height is 7.4 cm.
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