A triangle has two corners with angles of ( pi ) / 4 and ( 7 pi )/ 12 . If one side of the triangle has a length of 12 , what is the largest possible area of the triangle?

1 Answer
Mar 2, 2018

Area of the largest possible triangle is 98.34 sq.unit.

Explanation:

Angle between Sides A and B is /_c= pi/4=45^0

Angle between Sides B and C is /_a= (7pi)/12=105^0 :.

Angle between Sides C and A is

/_b= 180-(45+105)=30^0

For largest area of triangle 12 should be smallest side , which

is opposite to the smallest angle /_b :.B=12

The sine rule states if A, B and C are the lengths of the sides

and opposite angles are a, b and c in a triangle, then:

A/sina = B/sinb=C/sinc ; A/sina=B/sinb or

A/sin105=12/sin30 :. A= (12*sin105)/sin30~~ 23.18 unit

Now we know sides A=23.18 , B=12 and their included angle

/_c = 45^0. Area of the triangle is A_t=(A*B*sinc)/2

:.A_t=(23.18*12*sin45)/2 ~~98.34 sq.unit.

Area of the largest possible triangle is 98.34 sq.unit [Ans]