A triangle has sides A, B, and C. Sides A and B have lengths of 2 and 5, respectively. The angle between A and C is #(11pi)/24# and the angle between B and C is # (7pi)/24#. What is the area of the triangle?

1 Answer
Mar 15, 2018

The triangle does not exist...
Here's the area anyways:
#A= (5sqrt2)/2 un^2 approx 3.54 un^2#

Explanation:

Area of the triangle:
#A= 1/2a*b*sinC#
Let's determine angle C:
#(24pi)/24-(7pi)/24-(11pi)/24= pi/4#

Area of the triangle:
#A= 1/2(2)(5)sin(pi/4)=#
#A= (5sqrt2)/2 un^2 approx 12.37 un^2#

How do I know this triangle particularly does not exist?
Well:
The law of sines states:
SinA/a= SinB/b
Therefore:
#B= arcsin((SinA*b)/a)#
#B= arcsin((Sin((7pi)/24)*5)/2)= undef.#
Since Angle B cannot be computed, this triangle does not exist