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JavaScript JavaScript Foundations Numbers The Math Object

Posted by Marcus Sacco
Marcus Sacco
2,153 Points

No variable named "circumference" has been defined. Are you kidding?

Task: Create a variable named "circumference" and assign the correct value to it by using the "diameter" variable and Math.PI.

My submission for this challenge keeps throwing the above error. I cannot spot this problem for the life of me. Here is what the code looks like:

var diameter = 5.75,
          a = 17,
          b = 42,
          c = 1337,
          ageIfILiveToYear2100 = (new Date(2100, 0, 1) - new Date(1995, 5, 16, 7, 20)) / (1000 * 60 * 60 * 24 * 365.242);
var circumference = Math.PI(diameter);

I hope this formats correctly. EDIT: NOPE. (But there are mods who fix problems like that. - A mod)

3 Answers

Dino Paškvan
Dino Paškvan
Courses Plus Student 44,108 Points

Math.PI is not a function, it's a property (a constant), so it's not invoked with (). And the circumference of a circle is its diameter multiplied by the value of PI.

Try assigning the value of diameter multiplied by Math.PI to the circumference variable.

Marcus Sacco
Marcus Sacco
2,153 Points

Got it. Thanks, Dino.

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

im not sure if using the parenthesis like that for multiplication works (though JS isnt really my thing so who knows.) try using 

var circumference = Math.PI * diameter;
Jeff Busch
Jeff Busch
19,287 Points
Jeff Busch
Jeff Busch
19,287 Points

Hi Marcus,

No, they are not kidding

Jeff