Somebody help plz I need some help

Solve for x: 5/3 x = 20/21 it's fraction. remember to simplify your fraction

What is the perimeter of a rectangle if the length is 5 and the width is x?

An architect builds a model of a park in the shape of a rectangle. the model is 40.64 centimeters long and 66.04 centimeters wide. one inch equals 2.54 centimeters. use the ratio table to find the ratio of the length to the sum of the length and width in inches and in simplest form. length 40.64 width 66.04 a. 8: 21 b. 13: 21 c. 21: 13 d. 21: 8