Commercial dredging operations in ancient rivers occasionally uncover archaeological artifacts of great importance. One such artifact is Bronze Age spearheads recovered from ancient rivers in Ireland. A recent study gave the following information regarding discoveries of ancient bronze spearheads in Irish rivers.

River Bann Black water Erne Shannon Barrow
No of spearcheads 25 7 15 33 14

Required:
a. Make a Pareto chart for these data.
b. Make a circle graph for these data.