Math journal chapter 7 and 8

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# Math journal chapter 7 and 8 - PowerPoint PPT Presentation

Math journal chapter 7 and 8. ____(0-10 pts) Describe a ratio. Describe a proportion. How are they related? Describe how to solve a proportion. Describe how to check if a proportion is equal. Give 3 examples of each. Ratios: they compare two numbers by division .

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____(0-10 pts) Describe a ratio. Describe a proportion. How are they related? Describe how to solve a proportion. Describe how to check if a proportion is equal. Give 3 examples of each.

Ratios: they compare twonumbersbydivision.

Proportions: isanequationstatingthattwo ratios are equal.

Relationship: ratios relates two quantities together using a fractions

a proportion has a relationship between two quantities the equivalence of two ratios.

Checking: to check if a proportions are equal you have to cross multiply and obtain

The same result.

Ex:

x/2 = 40/16 x = 5 the proportion is equal.

x/5 = 10/6 x = 3 the proportion in not equal.

7/y = 21/27 y = 9 the proportion is equal.

_____(0-10 pts) Describe what it means for two polygons to be similar. What is a scale factor? Give at least 3 examples of each.

Twopolygonstobe similar: Fortwopolygonstobe similar theyneedtohave

Correspondingangles are congruent and theircorrespondingsidelenghts are

Proportional.

Scale factor: thescale factor describes howmuchthe figure isenlargedorreduced.

Ex:

1: Itis similar. 2: They are similar polygons 3: They are similar polygons.

____(0-10 pts) Describe how to find the scale factor for the perimeter and areas of similar figures. Give at least 3 examples of each one.

Similarity ratio: AB/DE = AC/DF = BC/EF = ½

Perimeter ratio: perimeter /perimeter

Are ratio : area/ area = ½ *2

_____(0-10 pts) Describe how to use similar triangles to make an indirect measurement. Give at least 3 examples.

Anindirectmeasurmentanymethodthat uses formulas, similar figures,

And / orproportionstomeasureanobject.

Theseis use becauseto use a trianglethatyou do knowtheremeasurments and that

Withthatyouonlyneedtoknowonemeasurment of theobjectyouwanttomeasure

becasueyou can use crossmultiply.

_(0-10 pts.) Describe the right triangle altitude proportionality theorem. Give at least 3 examples. Explain how the proportions can be used to solve real life problems.

Thealtitudetothehypotenuse of a righttriangleformstwotrianglesthat are

Similar tothe original triangle.

Theproportions can beusedtotosolve real life figures becauseifyou are climing

A mountain and youhave 20 ft of rope and youneedtofindouthowtallthemountainis

You use similar figures tofinditoput and seeifyouhaveenoghrope.

__(0-10 pts.) Describe the three trigonometric ratios. Explain how they can be used to solve a right triangle. What does it mean to solve a triangle? Give at least 3 examples of each. How are they used in real life?

The sin: the sin of anangleisthe ratio of thelenght of thelegopposite

Theangletothelenght of thehypotenuse.

Thecosine of anangleisthe ratio of thelenght of thelegadjacenttotheangle

Tothelenght of thehypotenuse.

Thetangent of anangleisthe ratio of thelenght of thelegoppositetheangletothe

Cos 60 = 0.99

Tan 30 =0.57

Sin 45 = 0.70

_____(0-10 pts.) Compare an angle of elevation with an angle of depression. How are each used? Give at least 3 examples of each

Anangle of elevationistheangleformedby a horizontal line and a line of sight

To a pointabovethe line.

Anangle of depresionistheangleformedby a horizontal line and a line of sightto a point

Belowthe line.