Which postulate or theorem can be used to prove that angle abc is congruent to angle def?

If two angles and the included side of one triangle are congruent to the corresponding parts of another triangle, then the triangles are congruent.

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,