To solve this problelm you must apply the proccedure shown below:
1. You must apply the formula for calculate the area of a triangle, which is:
[tex] Area=\frac{(base)(height)}{2} [/tex]
2. Now, substitute the values given in the problelm above into the equation:
[tex] Area=\frac{(6units)(7units)}{2} \\ Area=21units^{2} [/tex]
Therefore, as you can see, the answer is: [tex] 21units^{2} [/tex]
Answer: i belive the answer is D, i got it right on the test :) hops this helped