symmetry and similarity
DESCRIPTION
Symmetry and Similarity. At the right is a multiplication table with only the ones digit showing. Describe any rotations, translations reflections… Finish work: we begin in 10 minutes. Tessellations, briefly. This is sometimes called “tiling” the plane. - PowerPoint PPT PresentationTRANSCRIPT
Symmetry and Similarity
• At the right is a multiplicationtable with only the ones digitshowing.
• Describe any rotations, translationsreflections…
• Finish work: webegin in 10 minutes.
1 2 3 4 5 6 7 8 9
1 1 2 3 4 5 6 7 8 9
2 2 4 6 8 0 2 4 6 8
3 3 6 9 2 5 8 1 4 7
4 4 8 2 6 0 4 8 2 6
5 5 0 5 0 5 0 5 0 5
6 6 2 8 4 0 6 2 8 4
7 7 4 1 8 5 2 9 6 3
8 8 6 4 2 0 8 6 4 2
9 9 8 7 6 5 4 3 2 1
Tessellations, briefly• This is sometimes called “tiling” the
plane.
• A figure is repeated in such a way that there are no overlaps and no gaps.
In general• The sum of the angles about a point
must total 360˚.
• So, question: will every convex quadrilateral tessellate?
• Will regular hexagons tessellate?
• Will regular octagons?
Similarity• Do exploration 9.1 part 3 on page 239.
• Using geoboard paper draw TWO similar figures for a, b, d, f, and g only.
• Write a definition or a detailed description of what makes two figures similar.
Similarity• Figures that are similar have corresponding
parts--– The corresponding angles are congruent.– If each of the corresponding sides is also
congruent, then the two figures are congruent.– If each of the corresponding sides are in the same
proportion, then the two figures are similar.– If even one pair of corresponding sides is not in
the same proportion, then the figures are not similar.
• If the sun shines on a 6 foot man creating a 10 inch shadow, how long will the shadow be of a 40-foot cactus?
Not to scale
Measurement, Perimeter, Area
• In your groups, make a list of:
– All the measurement conversions you know;
– All the perimeter and area formulas you know.
What is measurement?• A measurement is determined by the number
of repeated units needed to fill a specific length, time, area, volume, weight, capacity, temperature, etc.
• The units we are accustomed to using are inches, seconds, square feet, cubic centimeters, pounds, tablespoons or Liters, degrees Fahrenheit, etc.
Conversions you should know!
• 3 teaspoons = 1 tablespoon;• 2 tablespoons = 1 liquid ounce;• 8 liquid ounces = 1 cup;• 2 cups = 1 pint; 2 pints = 1 quart; • 4 quarts = 1 gallon• 16 ounces = 1 pound; • 2000 pounds = 1 ton.
Conversions you should know!
• 60 seconds = 1 minute; • 60 minutes = 1 hour; 24 hours = 1 day• 12 inches = 1 foot; 3 feet = 1 yard;• 5280 feet = 1760 yards = 1 mile• Freezing: 32˚F = 0˚C; Boiling: 212˚F =
100˚C; Random: -40˚F = -40˚C
Metric vs. CustomaryKilo Hecto Deka Unit Deci Centi Milli
meter Liter gram
As you move to smaller units, there are more per unit, so multiply by 10.
As you move to larger units, there are fewer per unit, so divide by 10.
Ex: 56 mm = _____ m; 95 kg = _____ g; 39 L = _____ mL
Common Conversions• 1 inch is exactly 2.54 cm• 1 meter is about 39 in.• 1 mile is about 1.6 km• 1 kilometer is about 0.6 miles• 1 mL is about 1/4 teaspoon of water• 1 Liter is about a quart.• 1 mg is about the weight of a strand of hair.• 1 gram is about the weight of a raisin or small
paperclip.• 1 kilogram is about 2.2 pounds.