ABC is a 3 4 5 right triangle area = 1/2 3 * 4 units2
DEF is also a right triangle ....since arcos D = 3/5 EF = 3 so the area is the same as the first one !
Use cos law to find CB
then use Heron's rule to find the area of triangle ABC
Similar for DEF use cos law to find EF then heron's rule to find area
Agree with Guest..... this answer is incorrect.....(see better answer further down)
Yea I don't understand how to even approach this.....
I need help too