In the triangle shown below what is the approximate value of x

it's a right triangle so you use Pythagoras' theorem.

√28²-14²=

√784 - 196 =

√588

24.24 units (rounded 24.25)

your answer is 24.25 units

x^2 = 28^2 - 14^2

x^2 = 784 - 196

x^2 = 588

x = 24.25

Answer is C. 24.25 units

ca = ec

cpctc makes it so that corresponding parts of the triangle you proved to be equal are equal, the other options aren't part of the part of the triangles you proved to be equal.