The distance AB rounded to the nearest tenth

How can you find the conditional probability of a given b as the fraction of b’s outcomes that also belong to a, and interpret the answer in terms of the model? i just need a good explanation

The center of the circumscribed circle lies on line segment and the longest side of the triangle is equal to the of the circle.

Due to bad planning, two of the local schools have their annual plays on the same weekend. while 457 people attend one, and 372 attend the other, only 104 people were able to attend both. how many people went to at least one play?