How to Find the Area of Basic 2-D Figures

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Difficulty: Easy

Instructions

Things You'll Need:

• Calculators
• Measuring Tapes
• Erasers
• Graph Papers
• Notebooks
• Rulers
• Calculators
• Notebooks

1. Find the area of a square by finding the square of the length of one side. Example: The area of a square with a side length of 2 is 2 x 2 = 4.

2. Discover the area of a rectangle by multiplying the length of one side by the length of its adjacent side. Example: The area of a 3-by-5 rectangle is 3 x 5 = 15.

3. Compute one-half times the product of the length of the base and the height to find the area of a triangle. Example: The area of a triangle with base length 4 and height 9 is (1/2) x 4 x 9 = 18.

4. Multiply the length of the base by the height to find the area of a parallelogram. Example: The area of a parallelogram with base length 8 and height 5 is 8 x 5 = 40.

5. Find the area of a trapezoid by adding the lengths of the parallel lines, then multiplying the sum by one-half the height. Example: The area of a trapezoid with height 6 and parallel lines of length 3 and 7 is (1/2) x 6 x (3 + 7) = 30.

6. Multiply the square of the radius by pi to find the area of a circle. Example: The area of a circle with radius 4 is 4 x 4 x pi = 50.

7. Determine the area of an ellipse by multiplying pi by the product of the maximal and minimal radii. Example: The area of an ellipse with maximal radius 9 and minimal radius 6 is 9 x 6 x pi = 170.

Tips & Warnings

• Some area problems include units. We convert length units into area units by adding the word "square" before the length unit. Thus, inches become square inches, meters become square meters, and so on.

on 11/22/2005 For finding the area of a trapezoid use:

A=h(b1+b2)/2

Add the lengths of the 2 parallel sides.
Divide by 2 to get the average length of the parallel sides.
Multiply this by the height (distance between the parallel sides).