It is an abbreviation for quart.
principal(in terms of math)- the amount you borrow or deposit
HL in math mean hypotenuse leg
A quart is an out-of-date measure of volume (still used in the US) which is equivalent to a quarter of a gallon.
ask your math teacher
(whatever unit of length you're working with) cubed liter gallon quart pint
It
sum means the answer of a math problem
No.
neither
A rhombus.
Milimeters