Arectangular yard is 18 feet long. the area of the yard is 400.5 square feet. what is the width of the yard

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. 4x^2 + 20x + 25 = 0

Ineed with area of a circle a circular plate has a diameter of 6 inches. what is the exact area of the plate? a.3_ square inches b.6_ square inches c.36_ square inches d.9_ square inches

Me because i don't understand how to do it.: )