9514 1404 393
Answer:
B acute
Step-by-step explanation:
We can define a "form factor" for a triangle as ...
f = a² +b² -c²
where c is the longest side length. It will be interpreted as follows:
- negative -- obtuse triangle
- zero -- right triangle
- positive -- acute triangle
For this triangle, our "form factor" is ...
f = 15² +16² -21² = 225 +256 -441 = 40 . . . . a positive number
The triangle is Acute.
