NaN in javascript when finding the area of a triangle using two different variable. The output should be 25

JAVASCRIPT CODE:

// store the length1 value

var length1 = 10;

// store the length2 value

var length2 = 5;

//store the length3 value

var length3 = 1;

function doStuff(){

document.getElementById("classname").innerHTML = classname;

document.getElementById("triangle").innerHTML = getareaoftriangle();

}

function getareaoftriangle() {

return (length1 * length2) / 2;

}

Shapes Hi! Class name: Area of the Triangle: Area of the Circle: Area of the rectangle Grand total area of all the shapes: 0 Submit Now CSET3250 NaN 0 0