B. 2-D Shapes and their Areas
B. 2-D Shapes and their Areas
Understanding the meaning of area and knowing how to find the area of basic shapes are essential to success in determining the surface area of three-dimensional objects and determining the area of the base of a three-dimensional object when finding its volume.
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Area
the amount of space occupied by a two-dimensional shape |
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Another version of the formula for the area of a triangle is «math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«mi»A«/mi»«mo»=«/mo»«mfrac»«mrow»«mi»b«/mi»«mi»h«/mi»«/mrow»«mn»2«/mn»«/mfrac»«/math», where b is the base of the triangle and h is the perpendicular height. «math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«msub»«mi»A«/mi»«mrow»«mi»t«/mi»«mi»r«/mi»«mi»i«/mi»«mi»a«/mi»«mi»n«/mi»«mi»g«/mi»«mi»l«/mi»«mi»e«/mi»«/mrow»«/msub»«mo»=«/mo»«mfrac»«mrow»«mi»a«/mi»«mi»b«/mi»«/mrow»«mn»2«/mn»«/mfrac»«/math»and «math style=¨font-family:`Times New Roman`¨ xmlns=¨http://www.w3.org/1998/Math/MathML¨»«msub»«mi»A«/mi»«mrow»«mi»t«/mi»«mi»r«/mi»«mi»i«/mi»«mi»a«/mi»«mi»n«/mi»«mi»g«/mi»«mi»l«/mi»«mi»e«/mi»«/mrow»«/msub»«mo»=«/mo»«mfrac»«mrow»«mi»b«/mi»«mi»h«/mi»«/mrow»«mn»2«/mn»«/mfrac»«/math» can be used interchangeably for determining the area of a triangle. |
Some common area formulas are given below.
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These formulas are likely familiar to you as they were introduced in junior high math courses.
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Example 1 |
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Determine the area of a rectangle with a width of 1.50 m and a length of 2.25 m. Round your answer to the nearest thousandth of a square metre.
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Example 2 |
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What is the area of a triangle with a height of 4.45 cm and a base length of 6.0 cm? Round your answer to the nearest hundredth of a square centimetre.
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