C. 315 units^2
Step-by-step explanation:
The formula for the area of a triangle is:
[tex]A=\frac{1}{2}bh[/tex]
In this case, the base (b) will be 30 and the height (h) will be 21.
We can plug these numbers in the equation and make the 1/2 a .5.
[tex]A=.5*30*21[/tex]
A = 315
~
315 units^2
