Answer:
8.06
Step-by-step explanation:
Use the Pythagorean theorem:

The hypotenuse is always the slanted side, or c (x in this picture), but the other numbers can be interchanged. Doesn't matter.
Plug the numbers 4 and 7 into the formula.

Now evaluate them to get 
16+49=65
To get c, take the square root of 65

Easy you just divide it like a regular then put move the decimal to the left the number of times letters are behind it.
The thickness of a brand new US penny that hasn't been
worn down is 1.52 millimeters.
If you have a million pennies, there are many ways to arrange them.
You can pile them all in one pile, or shovel them into many piles, or
stack them up in any number of stacks up to a half-million stacks
with two pennies in each stack, or try somehow to stack them all up
in one stack that's a million thicknesses high.
Any stack with 'n' pennies in the stack is 1.52n millimeters high.
If you somehow succeed in stacking all million of them in one stack,
then the height of that stack would be . . .
(1,000,000) x (1.52 mm) = 1,520,000 millimeters
152,000 centimeters
1,520 meters
1.52 kilometers
(about 59,842.5 inches
4,986.9 feet
1,662.3 yards
7.56 furlongs
0.944 mile
all rounded)
It's a nonlinear because the x and y values are not increasing at the same ratio each time. This would be an example of a linear function:
x l 1 2 3 4 5 6
y l 3 6 9 12 15 18
As x increases by 1, y increases by a multiple of 3