If you're looking for the simplified version of the fraction, you have to factor both numerator and denominator.
The numerator is actually already a prime number, so we're good
The denominator factors as 
So, a 3 appears in both numerator and denominator. We can simplify it:

If you want to compute the approximated value of this fraction, simply plug these values into some calculator to get

Answer: 1,569.75
Step-by-step explanation:
6279÷4=1,569.75
:)
1st step is to find the radius, then substitute into the formula for area of a circle

to find the radius, just halve the diameter
The toy rocket hits the ground when h(t) = 0.
So, h(t) = 0 = -9t^2 + 81.
Solving the equation,
-9t^2 = -81
Dividing by -9
t^2 = 9
Taking the square root.
t = 3
The answer is 3 seconds.