Please show work

8. Use Heron's Area Formula to find the area of the triangle. (Round your answer to two decimal places.)

a =9, b =15, c =17

9. Use Heron's Area Formula to find the area of the triangle. (Round your answer to two decimal places.)

A =81\deg , b =73, c =42

11. Find a unit vector u in the direction of v. Verify that ||u||=1. v=(5,-12)

14a. Find the projection of u onto v. u=(8,4) v=(3,-6) projvu =

14b.Write u as the sum of two orthogonal vectors, one of which is projvu.

u = projvu +

16. Find the distance between the complex numbers in the complex plane.

4+ i,2+4i

17. Find the midpoint of the line segment joining the points corresponding to the complex numbers in the complex plane.

8+ i,2+3i

18a. Write the trigonometric form of the complex number. (Let0<=<2.)

3+3i