Answer:
C)3.4 mm
Explanation:
We are given that
Length of side of a triangle,a =4 mm
Length of side of a triangle, b=4 mm
The angle between two sides=

We have to find the length of third side of triangle.
Cosine law:

Substitute the values then we get


Hence, the length of third side of the triangle=3.4 mm
Option C is true.