# [SOLVED] Perimeter of an isosceles triangle

• October 20th 2008, 05:51 AM
fabxx
[SOLVED] Perimeter of an isosceles triangle
Hey guys,

This is on the Barrons SAT Math II Book page 21 #44

The vertex angel of an isosceles triangle is 35 degrees. The length of the base is 10 cm. How many cms are in the perimeter?

How do you do this problem? THanks in advance
• October 20th 2008, 06:27 AM
masters
Quote:

Originally Posted by fabxx
Hey guys,

This is on the Barrons SAT Math II Book page 21 #44

The vertex angel of an isosceles triangle is 35 degrees. The length of the base is 10 cm. How many cms are in the perimeter?

How do you do this problem? THanks in advance

Drop the perpendicular from the vertex angle to the base, bisecting the base and the vertex angle.

Each base angle = 72.5 degrees $\frac{180-35}{2}$

Now you have two right triangles and you know their angles and one side. Use trig to find the hypotenuse.