Its a common technique for remembering the order of operations. The abbreviation pemdas is turned into the phrase "Please excuse my Dear Aunt Sally". It stands for "Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction.
This is a ratio problem; the ratio of the length to width is constant (and therefore equal):
4 /6 = 15 / x
Now, with a ratio, we may do any allowable algebra operation: cross-multiply, invert both sides, multiply or divide both sides by the same amount, etc.
Let's cross-multiply:
4x = (15)(6)
x = 90/4
x = 22.5 in.
The formula for finding the volume of a sphere is 
If 40mm is the radius of the sphere, the volume will be about 
mm.
The answer is 4 1/3. Would you like an explanation?
Answer:
His wet feet froze the faster, and his exposed fingers numbed the faster, though they had not yet begun to freeze.
Step-by-step explanation:
Did this for edmentum and got it correct.
