Line p, parallel to the side AB of △ABC, intersects AC and BC at points D and E respectively. Find the area of △ABC, if AABD=a and AAEC=b.

Question

Line p, parallel to the side 

AB

  of △ABC, intersects 

AC

  and 

BC

  at points D and E respectively. Find the area of △ABC, if A_ABD=a and A_AEC=b.    

Answer 1

I don't understand where the 2nd A came from.

To get area you've got to get the length from the middle of an angle to a rt angle on the opposite side and multiply it by 1/2 the length of that side.