Triangle ABC is such that angle A is 81°, the side opposite, a, is 11cm and one of the other sides, b, is 12cm long. Are there two possible values for angle B?

I started working on this using the sine rule, and got (sin 81)/11 = (sin B)/12. I rearranged to get sin B = (12 sin 81)/11, which gave me a value for sin B of 1.077, but the sine curve has a maximum value of 1, so can anyone tell me what I've done wrong?

Question

Triangle ABC is such that angle A is 81°, the side opposite, a,  is 11cm and one of the other sides, b,  is 12cm long.  Are there two possible values for angle B?

I started working on this using the sine rule, and got (sin 81)/11 = (sin B)/12. I rearranged to get sin B = (12 sin 81)/11, which gave me a value for sin B of 1.077, but the sine curve has a maximum value of 1, so can anyone tell me what I've done wrong?

anonymous · Answer

Anyone able to help please?