<u>Angles that are vertical are basically neighbors that are across from each other (numbers across from each other). </u>
Angle <u><CFD</u> would be vertical to <EFA.
You can apply the Pythagorean theorem:
a^2 + b^2 = c^2
c is the longest side of the triangle
2.2^2 + 4.2^2 = 6.7^2
4.84 + 17.64 = 44.89
22.48 =/= 44.89
That is not a right triangle
The value of X would be 3.6 because if you divide the 4 by 2 to get the half triangle you now know the base and height for the triangle. Now you have to use tangent -1 to figure out the bottom right angle which is 56.3 degrees. Once you have the angle you can use Sin to figure out the missing side.