SOLUTION: The vertex angle of an isosceles triangle is 72°,and each of equal sides is 10 cm.Find the perimeter and the area of of the triangle.

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Question 567914: The vertex angle of an isosceles triangle is 72°,and each of equal sides is 10 cm.Find the perimeter and the area of of the triangle.
Answer by mananth(16946) About Me  (Show Source):
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let the vertex be A where the legs meet
legs are 10 cm each
B & C are the vertices of the base
Law of Sines
a/sin A = b/sin B = c/sin C
a/sin 72 = 10/Sin 54 = c/Sin 54
a= 10*sin 72/Sin 54
a= 11.75
So the perimeter = 11.75+10+10
perimeter = 31.75 cm