chap0901

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course Mth 152

12/14/2012 4:00PM

020.  ``q Query 20 

 

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Question:  `q Query  9.1.36  Given rays MO and OM 

How do you express the intersection of the two rays? 

How do you express the union of the two rays.

 

 

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Your solution: 

The ray MO starts at M and goes through O and continues forever. The ray OM starts at O and goes through M and continues forever. The intersection of the rays would make line segment MO because both rays have the line segment MO in common. The union of the two rays would make the line MO, which would continue for ever in both directions.

 

 

confidence rating #$&*: 3

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Given Solution: 

`aSTUDENT SOLUTION: 

 

The ray MO, designated by the letters MO with a single arrow over the top, originates at the point M, passes through the point O and continues forever. 

 

The ray OM, designated by the letters OM with a single arrow over the top, originates at the point O, passes through the point M and continues forever.

 

The two rays have in common the line segment OM, which would be designated by the letters OM with a 'bar' over the top.  This would be the intersection of the two rays.

 

The union of the two rays would form the line OM, which continues forever in both directions and is designated by the letters OM with a 'double arrow' over the top (a double arrow looks something like <-->).

 

 

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Self-critique (if necessary): OK

 

 

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Self-critique Rating: OK

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Question:  `q Query  9.1.54  lines SR and TP intersect at Q, where Q lies between S and R, and also between T and P. 

 

What are the names of the pairs of vertical angles for this figure?

 

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Your solution: 

All the angles are SQP, PQR, RQT, SQT. PQR and SQT makes a pair of vertical angles, and SQP and TQR makes a pair of vertical angles.

 

 

confidence rating #$&*: 3

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Given Solution: 

The point Q lies between S and R on the first line, and between T and P on the second.

 

The angles formed by these two intersecting lines, running clockwise around the figure, are SQT, SQP, PQR and RQT.

 

A pair of vertical angles consists two alternate angles from this list.  The only possibilities are

SQT and PQR

SQP and RQT

and these are the possible pairs of vertical angles.

 

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Self-critique (if necessary): OK

 

 

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Self-critique Rating: OK

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Question:  `q Query  9.1.60  Angles 5x - 129 deg and  2x - 21 deg are vertical angles. 

What is the value of x and how did you obtain it?

 

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Your solution: 

The angles are equal, so to find x I solved (5x - 129 = 2x - 21) = (3x - 129 = -21) = (3x = 108) = (x = 36)

 

 

confidence rating #$&*: 3

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Given Solution: 

Since the angles are vertical angles, they are equal to each other, therefore, I set them up to be equal to each other and then solved.  To check myself, I then substituted my answer in for x on both sides of the equation to make sure they were equal.

 

Starting with

 

5x - 129 deg = 2x - 21 deg

 

subtract 2x from both sides to get

 

3x - 129 deg  = -21 deg.  Add 129 deg to both sides to get

3x = 108 deg.  Divide both sides by 3 to get

x = 36 deg.

 

To check substitute 36 deg in for x in the equation and simplify, getting 51 deg = 51 deg.

 

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Self-critique (if necessary): OK

 

 

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Self-critique Rating: OK

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Question:  `q Query  9.1.72  The complement of an angle is 10 deg less that 1/5 of its supplement. 

What is the measure of the angle and how did you get it?

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Your solution: 

The complement of an angle is 90 - x, and the supplement is 180 - x. So to solve for x I worked out (90 - x = 1/5(180 - x) - 10) = (450 - 5x = 180 - x - 50) = (450 - 5x = 130 - x) = (-4x = -320) = (x = 80)

 

 

confidence rating #$&*: 3

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Given Solution: 

Let x be the degree measure of the angle.  Then the supplement is 180 deg - x; 10 deg less than 1/5 the supplement is 1/5(180 deg - x) - 10 deg.  The complement is 90 deg - x. 

 

So the equation is

 

90 deg - x = 1/5(180 deg - x) - 10 deg.  Multiplying both sides by 5 we get

450 deg - 5 x = 180 deg - x - 50 deg so that

450 deg - 5 x = 130 deg - x.  Adding x - 450 deg to both sides we get

-4x = -320 deg so that

x = 80 deg.

 

Checking against the conditions of the problem:

 

The complement of 80 deg is 10 deg.

The supplement of 80 deg is 100 deg; 1/5 the supplement is 1/5 * 100 deg = 20 deg, so the complement 10 deg is 10 deg less than the supplement 20 deg. **

 

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Self-critique (if necessary): OK

 

 

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Self-critique Rating: OK

 

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Question:  `q Query   Add comments on any surprises or insights you experienced as a result of this assignment.

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Self-critique (if necessary):

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Self-critique rating:

 

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Question:  `q Query   Add comments on any surprises or insights you experienced as a result of this assignment.

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Self-critique (if necessary):

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Self-critique rating:

#*&!

&#Very good responses. Let me know if you have questions. &#