Where are your choices? Is there more?
Answer:
I think it is A
Step-by-step explanation:
You are lazy... do it on your own.
We can write out a formula in order to solve this. Since sum represents addition, if x represents the unknown number, we can write the formula: x+51=-21. Then, to solve for x, you would subtract 51 from both sides to get x=-72 which is the final answer.
I FOUND YOUR COMPLETE QUESTION IN OTHER SOURCES.
SEE ATTACHED IMAGE.
Using Heron's Formula we can find the area of the triangle.
A = root (s (s-a) * (s-b) * (s-c))
s = (a + b + c) / 2
Where,
s: semi-perimeter
a, b, c: sides of the triangle
Substituting values:
s = (15 + 16 + 20) / 2
s = 25.5
s = 26
The area will be:
A = root (26 * (26-15) * (26-16) * (26-20))
A = 130.9961832
A = 130 u ^ 2
Answer:
The area of triangle ABC is:
C.
130 u ^ 2