Which classification best represents a triangle with side lengths 10 in., 12 in., and 15 in.?

It's an acute angled triangle.

Step-by-step explanation:

15^2 = 225

12^2 = 144

10^2 = 100

Adding:

10^2 + 12^2 = 244.

So as 15^2 <  12^2 + 10^2 this is an acute angled triangle.

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,