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
Answer:
13.9 sorry if I'm wrong just trying to help.
Step-by-step explanation:
first plug in your numbers
a*2+ b*2= c*2
12*12= 144
7*7=49
144+49= 193
square root of 193: 13.89244399
rounded to nearest tenth is 13.9
