X=4
First find the solution to (x+1) ft. I chose to guess the answer as 4 and it worked (you’ll have to guess). I then plugged 4 into the other equation 2x. It became 2•4. Solving give the side length of 8 ft. Then you have to check to make sure they both have the same area. To do this just solve the equations.
First rectangle- 4•4= 16 ft area
Second rectangle- 2•8 = 16 ft area
( I’m really sorry if this is confusing)
C, GHI because it is over 180 degrees and no triangle is over 180 degrees
Answer:
The third side is around 58.043
Step-by-step explanation:
Use the law of cosines: 
Plug in the two sides we know (into a and b) and the angle we know (into angle C).
Thus:
Use a calculator:


(Note: Make sure you're in Degrees mode.)
Answer:
Area of trangle = 1÷2 (9×12×sinRpo)
23= 1÷2 (108×sinRPO)