9514 1404 393
Answer:
7. obtuse
8. right
9. acute
Step-by-step explanation:
You can look at the difference ...
a^2 + b^2 -c^2
where c is the longest side. You can classify the triangle based on the result:
> 0 -- acute
= 0 -- right
< 0 -- obtuse
__
7. 7^2 +9^2 -15^2 = 49 +81 -225 = -95 ⇒ obtuse
8. 3^2 +4^2 -5^2 = 9 +16 -25 = 0 ⇒ right
9. 4^2 +5^2 -6^2 = 16 +25 -36 = 5 ⇒ acute
_____
There are several triangle solver apps and web sites available. Your graphing calculator may also solve triangles for you.
