You are using quotation which is assigning the variable with the string instead of the value. It should look something like this

PHP Code:
var objectHeight:Number 1;
var 
anotherVar:Number;

anotherVar objectHeight 1;
trace (anotherVar// 2; 
If you place quotes around objectHeight, it will treat it as string instead of a number. That is one reason I declare the variable and define its type, this way I will get a mismatch error if I try to shove a string in a variable defined for a number.