38.9k views
1 vote
(Helppppp)In a right ABC side AB is hypotenuse.

AB=14cm. BC=10cm.
Find what angle is bigger A or B.
Show two ways to solve this problem.

1 Answer

3 votes

Answer:

To find which angle is bigger, A or B, we can use trigonometric ratios or the Pythagorean theorem.

Method 1: Trigonometric ratios

We can use the trigonometric ratios of sine and cosine to find the values of sin A and sin B, and then compare them to see which angle is bigger.

sin A = BC/AB = 10/14 = 0.714

sin B = AC/AB = √(AB^2 - BC^2)/AB = √(196 - 100)/14 = √96/14 = 0.707

cos A = AC/AB = √(AB^2 - BC^2)/AB = √(196 - 100)/14 = √96/14 = 0.707

cos B = BC/AB = 10/14 = 0.714

Since sin A > sin B and cos A < cos B, we can conclude that angle A is bigger than angle B.

Method 2: Pythagorean theorem

We can use the Pythagorean theorem to find the length of AC, and then use the ratios of the sides to find the values of sin A and sin B.

AC^2 = AB^2 - BC^2 = 196 - 100 = 96

AC = √96 = 9.8 cm

sin A = BC/AB = 10/14 = 0.714

sin B = AC/AB = 9.8/14 = 0.7

Since sin A > sin B, we can conclude that angle A is bigger than angle B.

User Calvin Hu
by
7.2k points