Question

How do you solve the triangle if we are given a = 9, b = 12, c = 15?

Answer 1

You might recognize these proportions as being those of the standard `3:4:5` right angled triangle

which immediately gives us
`/_C = pi/2 (=90^o)`

`sin(/_A) = 12/15 = 0.8`
So
`/_A = arcsin(0.8)`

`sin(/_B) = 9/15 = 0.6`
So
`/_B = arcsin(0.6)`