Maths questions at GCSE level

Can someone help answer the following questions plzz

1)

The area of the pentagon is 8560mmsquared

Change 8560mmsquared top cmsquared

2)

Each side of another pentagon has a length of 101 mm,correct to the nearest millimetre.

(i)Write down the least possible length of each side.

(ii)Write down the greatest possible length of each side

3)Jane's car uses 1 gallon of petrol for every 40 miles. A gallon of petrol costs £3.20

(i) Work out the cost of petrol for Jane's 320 km journey.