In triangle ABC, angle C = 90 *, AB = 18cm, AC = 9cm What is angle A?
| September 21, 2021 | education
A triangle in which one angle is 90º is called rectangular.
To calculate the angle ∠A, it is most convenient to 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;
cos A = 9/18 = 1/2 = 0.5.
1/2 = 0.5 = cos 60º.
Answer: the degree measure of the angle ∠A is equal to 60º.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.
