The length of a rectangle is 4 more than 3 the width. if the perimeter of the rectangle is 18.4 cm, what is the area of the rectangle?

Im assuming you mean 4 more than 3 times the width so we'll make the width x and the length 3x + 4
perimeter is all of the sides added together so our equation is 2(x) + 2 (3x + 4) because there are two sides for length and two for width. we expand this equation to: 2x + 6x + 8 which equals 8x + 8. this is equal to 18.4 so 8x + 8 = 18.4
subtract each side by 8: 8x = 10.4 
divide each side by 8: x = 1.3
if x = 1.3 then the width = 1.3
if the width = 1.3 then the length = 7.9 because 3(1.3) + 4 = 7.9
area is length times width so 1.3 x 7.9 = 10.27
The area is equal to: 10.27

The answer is 1532.75