Nancy's 50-meter freestyle swim time was 28.004 seconds. Betty’s 50-meter freestyle swim time was 27.949 seconds. What was the difference between Nancy's and Betty's swim times? A. 0.088 second B. 0.055 second C. 0.099 second D. 0.801 second

Math it's appreciated. (picture provided)

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.

Use the squared identities to simplify sin^2x cos^2x