130 likes | 266 Vues
Please make a new notebook. Welcome to class. and. Begin working on the word search. iillLilillililiiiiiilllliiilililillliiillilililiiillllililililillliil. Let’s look at your Common Assessment #2. Today’s Vocabulary. Ratio – a comparison of two things – a/b….. a:b
E N D
Please make a new notebook Welcome to class and Begin working on the word search iillLilillililiiiiiilllliiilililillliiillilililiiillllililililillliil
Today’s Vocabulary Ratio – a comparison of two things – a/b….. a:b Extended ratio – a comparison of three or more things – a:b:c Proportion – two ratios set equal to each other – a/b = c/d Extended proportion – three or more ratios set equal to each other: a/b = c/d = m/n = x/y Extremes – the first and last terms in a proportion A/b = c/D A and D are the extremes Means – the middle terms in a proportion a/B = C/d B and C are the means Cross Products Property – multiplying the means and extremes to solve an equation. Remember you can only do this when you have a proportion.
ratio a c or a:c extended ratio a:c:x:y
proportion ab c d = abx c d y extended proportion = =
means ab c d = ab c d ab c d extremes =
Cross Products property ab cd = ad = bc
more of Today’s Vocabulary Similar figures – things that have the same shape but are generally a different size. Similar polygons – polygons that have the same shape but are a different size Scale - a ratio that compares each length in a scale drawing. Scale factor - The ratio of corresponding linear measurements of two similar figures. Scale drawing - A drawing where all lengths are proportional to their corresponding actual lengths.
similar figures similar polygons
scale drawing scale factor AC = AT = CT GO GD OD scale 16 = 12 = 8 4 3 2 4 = 4 = 4 Every 1 mm on this drawing, corresponds to 10 mm on the real horse. The scale factor is 4
let’s brush up and practice Write the ratio of the first measurement to the second measurement. Convert to inches: (14)(12) + 10 = 178 length of car: 14 ft 10 in. length of model car: 8 in 178 : 8 2900: .5 weight of car: 2900 lb weight of model car: 8 oz convert : 8 oz = ½ lb = .5 lb 3. There are 238 juniors at Torrington High School. The ratio of girls to boys in the junior class is 3:4. How many juniors are girls? How many are boys? 3x + 4x = 238 x = 34 There are 102 girls and 136 boys in the junior class.
3 = x 5 25 x = 15 x = 9 4 2 x = 18 x - 2 = 3 8 4 x = 8
Your assignment • 7-1 Practice worksheet • Don’t do 15 – 18 • 7-1 Reteach worksheet • Don’t do 14 - 16