What is the Resultant Force of Tensions in Two Fishing Lines?

[dan2xtermart]

Homework Statement

Two fishing lines hook onto one fish. The tensions in the lines are 20N and 30N, the angle between them being 30 degrees. Use a triangle of forces to find the magnitude of the resultant force of the tensions.

Homework Equations

cosine rule a^2 = b^2 +c^2 -2cbcos(theta)

The Attempt at a Solution

Triangle gives b=20, c = 30 and theta = 150.

Solving Resultant = 10root(6root(3) +13)


ANSWER IS GIVEN AS 10root(7), don't know how they get to this.

 

[Doc Al]

Solving Resultant = 10root(6root(3) +13)

Your answer is correct.