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Measuring Length and Distance in Metric Units Some of the tools used to measure length and distance are a metric ruler, a meter stick and a metric tape measure. Metric Units of Length Measurement • • • • • • • Meter (m) – Unit of measurement (starting point) Millimeter (mm) – (1 thousandth of a meter, 0.001, 10-3) Centimeter (cm) – (1 hundredth of a meter, 0.01, 10-2) Decimeter (dm) – (1 tenth of a meter, 0.1, 10-1) Decameter (dam) – (ten meters, 10, 101) Hectometer (hm) – (1 hundred meters, 100, 102) Kilometer (km) – (1 thousand meters, 1000, 103) • The units decimeter, decameter and hectometer are not used as often as the other units. • Meters or kilometers are used to measure longer distances or longer things such as school buses. •For measuring longer distances, meter sticks can be placed one after another along the distance, counting the total number. •Smaller divisions of the meter (millimeters and centimeters) are used to measure the length of shorter distances or things (like pieces of chalk or height of a school desk). To put these measurements into perspective we can compare them to everyday objects. 1 centimeter is about the width of an average person’s thumbnail 1 millimeter is about the thickness of a dime This drawing shows 1/10th of a meter stick, a decimeter (dm). It has 10 centimeters (cm) and each of those centimeters has 10 millimeters (mm). The arrows indicate specific mm locations. Length/Distance • Kilometers (thousands of meters....Fort Worth to Dallas TX, 50 km) • Meters (a school bus, ~10 m) • Centimeters (top of an average school desk, about 70 Cm) • Millimeters (width of a dime, 1 mm) Metric Conversions • To convert larger units to smaller ones , you MULTIPLY by units of 10 • To convert smaller units to larger ones you DIVIDE by units of 10 – Example: 1000 kilometer 100 10 hectometer decameter 1 Units (meters) 0.1 0.01 0.001 decimeter Centimeter millimeter – To convert 2 meters to centimeters (1 hundredth of a meter), you multiply by 100: • 2 x 100 = 200 cm (2 meters = 200 centimeters) – To convert 3 millimeters (1 thousandth of a meter) to meters, you divide by 1000 • 3 ÷ 1000 = 0.003 m (3 millimeters = 0.003 m) OR • Find out how far apart the two prefixes are on the line above. For example, kilo and hecto are one place apart, kilo and deka are two places apart, etc. • Move the decimal point to the left to convert smaller units or right to convert larger units by the number of places you found in the previous step. If there is no decimal in the number, assume it's after the last digit in the number. 1000 kilometer 100 10 hectometer decameter 1 Units (meters) 0.1 0.01 0.001 decimeter Centimeter millimeter Example #1 • To convert 1 kilometer to meters (convert larger to smaller), move the decimal 1 place to the RIGHT and add zeros where needed for the number of places you move down the table. Decimal Point Start 1 kilometer 0 0 hectometer decameter End 0 meter • 1 kilometer = 1000 meters decimeter Centimeter millimeter Example #2 • To convert 1 millimeter to meters (convert smaller to larger), move the decimal 1 place to the LEFT and add zeros where needed for the number of places you move down the table. Decimal Point End kilometer hectometer decameter meter • 1 millimeter = 0.001 meters 0 0 Start 1 decimeter Centimeter millimeter Convert the following measurements • 2 meters to centimeters 200 cm _________ • 4 kilometers to meters 4000 m _________ • 7 meters to millimeters 7000 mm _________ • 5 centimeters to meters 0.05 m _________ • 3 decimeters to meters 0.3 m _________ 0.08 dm • 8 millimeters to decimeters _________ We will now measure length/distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Stated as centimeters We will start by measuring distance, first by finding the correct millimeter and stating the answer in centimeters for “A” through “G”. First, “A”. Stated as centimeters We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. First, “A”. Stated as centimeters 18 mm 1.8 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “B”. Stated as centimeters 18 mm 1.8 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “B”. Stated as centimeters 18 mm 32 mm 1.8 cm 3.2 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “C”. Stated as centimeters 18 mm 32 mm 1.8 cm 3.2 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “C”. Stated as centimeters 18 mm 32 mm 44 mm 1.8 cm 3.2 cm 4.4 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “D”. Stated as centimeters 18 mm 32 mm 44 mm 1.8 cm 3.2 cm 4.4 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “D”. Stated as centimeters 18 32 44 59 mm mm mm mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “E”. Stated as centimeters 18 32 44 59 mm mm mm mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “E”. Stated as centimeters 18 mm 32 mm 44 mm 59 mm 75 mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm 7.5 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “F”. Stated as centimeters 18 mm 32 mm 44 mm 59 mm 75 mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm 7.5 cm We will start by measuring distance, first by finding the correct millimeter and then then stating the answer in centimeters for “A” through “G”. Then, “F”. Stated as centimeters 18 mm 32 mm 44 mm 59 mm 75 mm 87 mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm 7.5 cm 8.7 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “G”. Stated as centimeters 18 mm 32 mm 44 mm 59 mm 75 mm 87 mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm 7.5 cm 8.7 cm We will start by measuring distance, first by finding the correct millimeter and then stating the answer in centimeters for “A” through “G”. Then, “G”. Stated as centimeters 18 mm 32 mm 44 mm 59 mm 75 mm 87 mm 96 mm 1.8 cm 3.2 cm 4.4 cm 5.9 cm 7.5 cm 8.7 cm 9.6 cm How long is Mr. Frog? 6.9 cm or 69 mm How long is this fish in millimeters? 60 mm How many centimeters is that? 6 cm The butterflies wing 37 span is _________mm or stated in centimeters is 3.7 ____________cm. The caterpillar’s length in millimeters 21 mm or stated in centimeters is _________ is ____________. 2.1 cm Some rulers start at the very end of the stick and others have a small space before the actual ruler starts. The placement of one of these screwdrivers will give you the wrong answer for the screwdriver’s length. • Is this screwdriver 90 millimeters long (9 cm)? OR • Is it 94 millimeters long (9.4 cm)? 94 millimeters long (9.4 cm) The edge of the screwdriver must be put at the “0” of the ruler What is the length of this tooth pick? In millimeters? Stated in centimeters? 65 mm 6.5 cm What is the length of this paper clip in millimeters? Stated in centimeters? 30 mm 3 cm •Here is a little “pop” quiz as we finish discussing the measurement of length. •In pairs, measure your height with a meter stick or metric measuring tape. •How tall are you are in these metric length units? • meters • centimeters • millimeters