PowerPoint Presentation

Nikko Paolo Rodriguez1

Area3

Area

-The amount of space inside the boundary of a flat (2-dimensional) object such as a triangle or circle.

Rectangle

To find the area of a rectangle, multiply the length by the width.

The formula is: A= L x W

Example:

The length of a rectangle is 10m and the width is 7m. Find its area.

A= L x WA=(10).(7)A=70m26

Square

A square is a rectangle with 4 equal sides. To find the area of a square, multiply the length of one side by itself.

The formula is:A=s2 or A=sxs

where A is the area, s is the length of a side

Example:

The length of a one side of a square is 8m. Solve for its area.

A= s.sA= 8x8A=64m2

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Parallelogram

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, multiply the base by the height.

The formula is:A=bxh, where b is the base, h is the height

Example:

Find the area of a parallelogram with a base of 21 centimeters and a height of 14 centimeters.

A= bxhA= 21x14A=294cm2

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Triangle

A triangle is a three-sided polygon. To find the area of a triangle, multiply the base by the height, and then divide by 2.

The formula for the area of a triangle is:

Example 1:Find the area of anacute trianglewith a base of 15 inches and a height of 4 inches.Solution:A=1/2(15 in)(4in)A=1/2(60 in2)A= 30 in2

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Circle

The area of a circle is all the space inside a circle's circumference. The formula to find a circle's area is:

A=r2

Example:

What is the area of a circle with radius of 3 m ?

Area = r2 = 32 = (3 3) = 3.14159... 9 = 28.27 m2

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Find the area of the ff. plane figures:

A circle with radius of 2.5m

A triangle with base of 5m and height of 7m.

A parallelogram with b=12m and h=8m.

A trapezoid with b1=13m, b2=20m, and h=14.

A circle with diameter of 8cm

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1. Find the area of the shaded region.

2.

3.

Assignment:

Solve the ff. problems:

1) The area of a parallelogram is 110 m2. The base is 12 m. Find its corresponding height. (answer correct to 2 decimal places)

2) If a triangle has an area of 45cm2 and base of 5 cm, what is its height?