What is the area of a regular pentagon with a side length of 7 feet and a length from the center to a vertex of 6 feet?

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of