If you look at the attached graphic, you will see that the altitude (or height) of an equilateral triangle is:
Height = side length * sq root (3) / 2
Area = side^2 * sq root (3) / 4
It works because 7 x 9 x 10 is the same thing as 7 x 90, since 9 x 10 is just 90. So basically he is just writing more but the answer will still be the same.
Answer:
The maximum height of the arrow is 125 feet.
Step-by-step explanation:
The pathway of the arrow can be represented by the equation,
.....(1)
Where h is height in in feet and t is time in seconds.
It is required to find the maximum height of the arrow. For maximum height,
.
So,

Put t = 2.5 s in equation (1). So,

So, the maximum height of the arrow is 125 feet.