Add 3.5 to 14.9------------
Answer:
3x + 30
Step-by-step explanation:

3x + 30 would be an equivalent expression.
Hope this helps.
First you need to know that the internal angles of a triangle always equals 180°. Therefore:
15+45= 90°
Then since the angles should equal 180, you do:
180-90=90
So the missing angle equals 90°
For this case what you should know is that by definition the volume of the cone is given by:
V = ((pi) * (r ^ 2) * (h)) / (3)
Remembering that:
r = d / 2
Substituting the values:
V = ((pi) * ((d / 2) ^ 2) * (h)) / (3)
V = ((pi) * (((10) / 2) ^ 2) * (12)) / (3)
V = 314.16 ft ^ 3
Answer:
V = 314.16 ft ^ 3
The nearest option is:
300 cu. ft