Question 728416
The vertex angle of a triangle is three times the measure of either base angle. Find the area if the measure of the congruent sides are 14 in.	
	
For Isoselese triangle	
base=a	
legs=b	
base angle=beta	
vertex angle=alpha

sum of 3 angles of triangle=180

	2*beta+alpha=180

altitud=h	S=a*h/2

Area=S	S=(b^2/2)*sin alpha degrees
	
Sum of angles of triangle=180	
2*beta+alpha=180

now alpha=3*beta	
3*beta+2*beta=180	
5*beta=180	
beta=180/5=36 degrees	
And alpha=3*36=108 degrees	
	
S=a*h/2	
S=(b^2/2)*sin alpha	
=(14^2/2)*SIN108	b is congruent side
93.1392