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Finding the Area of Shapes 8 th Grade Mathematics Megan Naughton. Area is the size of a surface. It is the amount of space inside the boundary of a flat, 2-dimensional, object. Click on a shape to learn how to calculate it’s area:. Square. Circle . Parallelogram. Rhombus. Triangle.
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Finding the Area of Shapes8th Grade MathematicsMegan Naughton
Area is the size of a surface. It is the amount of space inside the boundary of a flat, 2-dimensional, object. Click on a shape to learn how to calculate it’s area: Square Circle Parallelogram Rhombus Triangle Trapezoid Ellipse Rectangle Review Question
Squares s All four sides of a square are of equal length. Therefore, in order to find the area of a square you multiply side x side. Or s
Circles The radius (r) or a circle is equal to half of its diameter. In order to find the area of a circle you multiply pi x r x r. Area = Or Area Pi r
Parallelograms A parallelogram is a 4-sided shape formed by two pairs of parallel lines. Opposite sides are equal in length and opposite angles are equal in measure. To find the area of a parallelogram, you multiply the base (b) by the height (h). h b
Trapezoids A trapezoid is a quadrilateral that has two parallel sides. To find the area of a trapezoid you first add the bases together (b1 + b2) and divide the sum by two. Then you multiply by the height (h). b1 h b2
Triangles Triangles are made up of three sides. In order to find the area of a triangle you multiply ½ by the base (b) and the height (h). h b
Rhombuses A rhombus is a parallelogram with four equal sides. To find the area of a rhombus, you must multiply the base (b) by the height (h). h b
Ellipses An ellipse is like a stretched circle with longer and flatter sides. To find the area of an ellipse, you multiply the semi major axes (a and b). These semi-major axes are half the lengths of, respectively, the largest and smallest diameters of the ellipse. You then multiply that by pi. b a
Rectangles A rectangle is a quadrilateral with opposite sides that are parallel and congruent. In order to find the area of a rectangle, you must multiply the length (l) by the width (w).
Review Question Find the area of this cookie using pi = 3.14. The radius of the cookie is 1.5 inches. Round your answer to the nearest tenth. A) B) C)
That area is too small. Go back and try again! Back to Question
That area is too large. Go back and try again!
Great work! is the correct area of the cookie! Click to Continue
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