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### Triangle Perimeter and Surface Area Formulas

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### Square Perimeter and Surface Area Formulas

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### Rectangle Perimeter and Surface Area Formulas

The perimeter ( P ) is the distance around the outside of the rectangle.

**P = 2h + 2w**

Area = h x w

Area = h x w

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### Parallelogram Perimeter and Surface Area Formulas

The perimeter ( P ) is the distance around the outside of the parallelogram.

**P = 2a + 2b**

The height ( h ) is the perpendicular distance from one parallel side to it's opposite side.

**Area = b x h**

It is important to measure the correct side in this calculation. In the figure, the height is measured from side b to the opposite side b, so the Area is calculated as b x h, not a x h. If the height was measured from a to a, then the Area would be a x h. Convention considers the side the height is perpendicular to is called the 'base' and usually denoted with a b.

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### Trapezoid Perimeter and Surface Area Formulas

The perpendicular distance between the two parallel sides is called the height ( h ).

**Perimeter = a + b**

Area = ½( b

_{1}+ b_{2}+ cArea = ½( b

_{1}+ b_{2}) x h06

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### Circle Perimeter and Surface Area Formulas

Circumference ( c ) is the distance around the outside of the circle.

Diameter ( d ) is the distance of the line through the center of the circle from edge to edge.

Radius ( r ) is the distance from the center of the circle to the edge.

The ratio between the circumference and the diameter is equal to the number π.

**d = 2r**

c = πd = 2πr

Area = πr

c = πd = 2πr

Area = πr

^{2}07

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### Ellipse Perimeter and Surface Area Formulas

The shortest distance between the center of an ellipse to the edge is called the semiminor axis ( r

_{1})

The longest distance between the center of an ellipse to the edge is called the semimajor axis ( r

_{2})

**Area = πr**

_{1}r_{2}08

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### Hexagon Perimeter and Surface Area Formulas

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