Pls help i dont understand

Will give are given that xy is parallel to zw. if xz is a transversal that intercepts xy and zw, angle angle alternate interior angles. since xy is parallel to zw, we know that these angles are we also know that angle xvy and angle zvw are , and thus congruent. we can conclude that △xyv ~ △zwv using the similarity theorem.

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. what distance from city a is the point where the truck and the car will meet?