Mystic Roses

Table describing the relationship between the points on a circle and the number of lines needed to connect them

Points	Lines	
3	3	
4	6	
5	10	
6	15	
7	21	
8	28	
9	36	
10	45	
11	55	
12	66	
100	4950	

Charlie and Alison
	Both Charlie’s and Alison’s methods work as they both achieved correct results. However, Charlie’s is perhaps more efficient, as the calculation is faster. Charlie’s calculation can be described as the following formulas: 
½ n (n-1)  = n(n-1)
                             2
where n is the number of points on the circle. 
Alison’s method was also correct, however for larger numbers can be very tedious. The advantage of her method is that people won’t risk confusion with variables. 
The number of points needed for a 100-pointed mystic rose is 4950. I figured this out by calculating 100(100-1)= 100(99)= 9900
Then I divided 9900 by 2, which equals 4950.