Use the digits 4,3,7 and 5 to make the largest 4 digit even number possible.. use each digit once

Asoccer ball manufacturer wants to estimate the mean circumference of soccer balls within 0.1 in

On average, how many more hits will he get when he bats 100 times at home during the day as opposed to 100 times away at night?

Given: △acm, m∠c=90°, cp ⊥ am , ac: cm=3: 4, mp-ap=1. find am.