Question

Solve the right triangle using the information given. Round answers to two decimal places, if necessary. a = 4, b = 6; Find c, α, and β.

Answer 1

Explanation:

first, remember Pythagoras :

c² = a² + b²

c is the Hypotenuse (the side opposite of the 90° angle).

a and b are the legs.

so, in our case

c² = 4² + 6² = 16 + 36 = 52

c = sqrt(52) = 7.211102551... ≈ 7.21

and then remember the law of sine :

a/sin(A) = b/sin(B) = c/sin(C)

a, b, c are the sides, A, B, C are the corresponding opposite angles (here also called alpha, beta. gamma would be the 90° angle).

so,

4/sin(alpha) = c/sin(90) = c

4 = c×sin(alpha)

sin(alpha) = 4/c = 4/7.211102551... = 0.554700196...

alpha = 33.69006753...° ≈ 33.69°

we don't need to do that much calculation for the third angle beta, as we know the sum of all angles in a triangle is always 180°.

so,

180 = alpha + beta + 90 = 33.69 + beta + 90

90 = 33.69 + beta

56.30993247... = beta ≈ 56.31°