Answer:
[tex]2\sqrt{5}[/tex]
Step-by-step explanation:
The picture (attached) shows two isosceles right triangles, so the altitude marked x splits the bottom side in half, 4 units and 4 units.
Each triangle is a right triangle with one leg of length 4, hypotenuse 6. Use the Pythagorean Theorem (leg)^2 + (leg)^2 = (hypotenuse)^2.
[tex]4^2+x^2=6^2\\16+x^2=36\\x^2=20\\x=\sqrt{20}\\x=2\sqrt{5}[/tex]
