2x+38=180
2x=142 (or x+x=142 from which 2x=142)
x=71
The unknown angles are each 71
You know this answer is logical as, since two sides are 21 it hints that we are looking at an equilateral triangle, which means two of its angles will be the same
The answer would be a bc 600/800 simplified is 3/4
If you simplify 256 you get 16 you have to square root it
Answer:
I got 0.3428571429
Step-by-step explanation:
I got it by inputting (2/5)*(6/7) into my calculator, but if you need more let me know
When plugging this into the calculator, you find:

The answer would be 8.9.