Answer: 20.8
Step-by-step explanation:
Since it is an equilateral triangle, we know the bottom is also 24. We also know that line E is bisecting the base. So using the smaller right triangle we know that the hypotenuse is 24 and one leg is 12. So use the Pythagorean theorem.
[tex]a^{2} +b^{2} =c^{2} \\12^{2} +b^{2} =24^{2} \\144+b^{2} =576\\b^{2} = 432\\b= 20.8[/tex]
