That gives us pr² which is equal to the area of the rectangle which is equal to the area of the circle. The area of a circle is the plane region bounded by the circles circumference. Area and circumference of a circle.
The length and width of the rectangle are 10 in and 4 in respectively so its area is A 104 40 The area of the semi-circle is one-half the area of a circle.
Circle worksheets videos tutorials and formulas involving arcs chords area angles secants and more. Circle Area p r 2 Circumference 2 p r r radius. Rectangle Area w h w width h height. If you know the circumference of a circle you can use a revision of the formula for the area of a circle.