In triangle ABC, angle C is straight, AC = 9, cosA = 0.3. Find AB.
| February 4, 2021 | education
A triangle in which one angle is 90º is called rectangular.
In order to calculate the length of the hypotenuse AB, we use the cosine theorem. The cosine of an acute angle of a right-angled triangle is the ratio of the adjacent leg to the hypotenuse:
cos A = AC / AB;
AB = AC / cos A;
AB = 9 / 0.3 = 30 cm.
Answer: the length of the hypotenuse AB is 30 cm.
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