Help please a

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4

8.74 rounded to the nearest whole number

Technicians have installed a center pivot, circular irrigator for a farm that covers 25 acres. a.) how long is the irrigation boom (in feet) from the center pivot to its farthest extent? b.) if the irrigation boom makes 4 full revolutions in a day, how many miles does the end of the boom travel in 5 days?