Answer: OPTION C.
Step-by-step explanation:
The area of a triangle can be calculated with the following formula:
[tex]A=\frac{bh}{2}[/tex]
Where "b" is the base of the triangle and "h" is the height of the triangle.
You know that all the triangles that compose the large triangle are equal.
According to the information given in the exercise, the base and the height of any small triangle are:
[tex]b=6\ in\\h=7\ in[/tex]
Therefore, the area of any of them is:
[tex]A=\frac{(6\ in)(7\ in)}{2}\\\\A=21\ in^2[/tex]
Since there are 4 equal triangles, you need to multiply the area obtained by 4 in order to find the area of the large triangle. This is:
[tex]A_{large}=4(21\ in^2)\\\\A_{large}=84\ in^2[/tex]
