Question

In a triangle, suppose we know that side b=3 feet, side c=2 feet, and that angle A=140o. According to the Law of Cosines, the length of side a is approximately?

Answer 1

Answer:

The length of third side of triangle is 4.195 feet.

Step-by-step explanation:

In a triangle as shown in the figure the law of cosines states that

$a^{2}=c^{2}+b^{2}-2bccos(A)$

Since it is given that

b = 3 feet

c = 2 feet

A = $140^{o}$

Using these values in the above equation we get

$a^{2}=2^{2}+3^{2}-2\times 3\times 2cos(140)\\\\\therefore a^{2}=17.596\\\\a=4.195feet$