#1**0 **

ABC is a 3 4 5 right triangle area = 1/2 3 * 4 units^{2}

DEF is also a right triangle ....since arcos D = 3/5 EF = 3 so the area is the same as the first one !

Guest Apr 11, 2022

#3**0 **

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

Guest Apr 11, 2022

#4**0 **

Agree with Guest..... this answer is incorrect.....(see better answer further down)

Guest Apr 11, 2022