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
V = 1/3 × (pie) × radius^2 × height of cone
Answer:

Step-by-step explanation:
2 + m
Rewrite with variable first.
m + 2
m + 2
Can’t be simplified further.
m - (-2)
Distribute negative sign.
m + 2
-2-m
Rewrite with variable first.
-m - 2
The last expression is not equivalent to m+2.