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Measurement. Chapter 8. Outcomes. D1: solve indirect measurement problems, using proportions D2: solve measurement problems, using appropriate SI units D3: estimate areas of circles D4: develop and use the formula for the area of a circle
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Measurement Chapter 8
Outcomes • D1: solve indirect measurement problems, using proportions • D2: solve measurement problems, using appropriate SI units • D3: estimate areas of circles • D4: develop and use the formula for the area of a circle • D5: describe patterns and generalize the relationships between areas and perimeters of quadrilaterals and areas and circumferences of circles • D6: calculate the areas of composite figures • D7: estimate and calculate surface areas and volumes of right prisms and cylinders • D8: measure and calculate surface areas and volumes of composite 3-D shapes
Metric Conversions • Metric units are very nice to work with, since they are all multiples of ten of each other. • The basic units are meters (for length), grams (for mass or weight), and liters (for volume).
Metric Prefixes • We use the following prefixes to describe the units we are dealing with: • kilo-, hecto-, deka-, deci-, centi-, and milli-. • To convert between the various prefixes, just move up and down this list of prefixes, moving the decimal point as you go.
Metric Staircase kilo .001 hecto .01decimal point moves to the right deka .1 Basic Unit (m, l, g) 1 deci 10 centi 100 decimal point moves to the left milli 1000
Example: • Since each step is ten times or one-tenth as much as the step on either side, we have: • 1 kilometer = 10 hectometers
You try these… • 2.5 km = ? m • 100cm = ? km • 5m = ? mm
What is perimeter? • Perimeter is the sum of the lengths of all the sides of a polygon. • It is the total length around an object.
Example… Find the perimeter of the rectangle with side lengths of 4m and 2m. 2m 4 m The perimeter would be 2m + 4m + 2m + 4m = 12m
What is area? • Area is the number of square units needed to cover a surface. 2m 4m The area of this rectangle can be found by using the equation A = l x w Therefore A = 4m x 2m = 8m2
You try these…(find area and perimeter) • Rectangle with sides 3cm and 7cm • Square with sides 5m • Rectangle with sides 4m and 3m
What about triangles??? • Can you use the same formulas for a triangle?
Area of a triangle • Area of a triangle is A = ½ b x h 8cm 4cm Area = ½ (4cm)(8cm) = 16cm2