NumbersEdit

• The equation 6*π + y^2 = 61985/100 + (1197 * 15) appears on a chalkboard.

solution is y = 136.22

There have been a number of different solutions posted for y. Here is a plain language explaination for y=136.22. If anyone supports a different solution, please state your case.

6*π + y^2 = 61985/100 + (1197 * 15)

First we can take care of the easily calculable stuff.

since (1197*15) = 17955, we can substitute "(1197*15)" with "17955" like this:

6*π + y^2 = 61985/100 + 17955

since 61985/100 = 619.85, we can substitute "61985/100" with "619.85" like this:

6*π + y^2 = 619.85 + 17955

since 619.85 + 17955 = 18574.85, we can substitute "619.85 + 17955" with "18574.85" like this:

6*π + y^2 = 18574.85

since π = ~3.1415, we can substitute "π" with "3.1415" like this:

6 * 3.1415 + y^2 = 18574.85

since 6 * 3.1415 = 18.85, we can substitute "6 * 3.1415" with "18.85" like this:

18.85 + y^2 = 18574.85

since 18.85 + y^2 = y^2 + 18.85, we can write it that way to make things more clear like this:

y^2 + 18.85 = 18574.85

if adding 18.85 to some number (y^2) gives us "18574.85", then not adding it would give us "18574.85 - 18.85" like this

y^2 + 18.85 = 18574.85 - 18.85

since 18574.85 - 18.85 = 18556, we can substitue "18574.85 - 18.85" with "18556" like this:

y^2 + 18.85 = 18556

we can also get rid of the strikethrough part like this:

y^2 = 18556

since y^2 means y * y, we can substitute "y^2" with "y * y" like this:

y * y = 18556

so we have a number that when multiplied by itself gives us 18556

well, 136.22 * 136.22 = ~18556

so "y" should equal 136.22

• y = 136.22

This answer is incomplete. Taking the square root of y^2 implies that the answer can be negative as well as positive. -136.22 is a valid longitude for the US. Also, by using Y instead of X, the implication is one of verticality, as with longitude. 71.50.174.72 21:01, April 24, 2010 (UTC)Perchprism

-136.22 only crosses the US at the Alaska panhandle near Juneau, so unlikely to be a longitude, I would have thought. Doublecross 18:45, May 23, 2010 (UTC)

Added -136.22 UKver2.0 12:06, April 26, 2010 (UTC)