Final answer:
To find the total number of members in the ski club, a proportion is used where 26% corresponds to 13 members, leading to the calculation of the entire membership, which is found to be 50 members.
Step-by-step explanation:
The question is asking to calculate the total number of members in the ski club based on the percentage that signed up for a trip to Park City. We are told that 13 members represent 26% of the club's total membership. To find the total number of members, we can set up a proportion where 26% (or 0.26 in decimal form) is to 13 members as 100% is to the total number of members (which we'll call x).
The proportion is 0.26 / 13 = 1 / x, which can be solved for x by cross-multiplication:
0.26x =

x = 13 / 0.26
x = 50
Therefore, there are 50 members in the ski club.