Geometry

a. 5
b. 10
c. 15
d. 20

Look at the following graph of the given equation. determine whether the equation is a function. explain why or why not.

1. 2. ∠b and ∠y are right angles. 3.? 4.? which two statements are missing in steps 3 and 4? ∠x ≅ ∠c △abc ~ △zyx by the sas similarity theorem. ∠b ≅ ∠y △abc ~ △zyx by the sas similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem.

I’m really confused and need your assist me with this question i’ve never been taught