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**demha****Member**- Registered: 2012-11-25
- Posts: 195

This is my Geometry lesson. I could use some help checking to see if I got them right or wrong. There are two here I do not know how to solve which I could use help with.

1. 87 - I said C

A 77

B24

C93

D47

E 31

F 48

2. 160 - I said A

A 10

B20

C30

D40

E 50

F 60

3. 68 - I said E

A 851

B295

C302

D574

E 112

F 638

4. 174 - I said D

A 3

B4

C5

D 6

E 7

F 8

5. a - Not sure how to solve, need help

A 180-a

B180/2

C 179*a

D 179+a

E 60

F pi

Find the complementary angles of the following.

6. 53 - I said F

A 90

B32

C 25

D 45

E 18

F 37

7. 12 - I said B

A 46

B78

C98

D31

E 52

F 64

8. 73.5 - I said A

A 16.5

B34.2

C29.4

D17.7

E 57.9

F 11.3

9. 23.7 - I said A

A 66.3

B70.1

C42.5

D83.9

E 54.8

F 36.2

10. a - Also not sure how to solve this one

A 90/a

Ba-90

Ca/2

D90-a

E 90-2

F a^2

---

I could also use some help understanding how to solve this. I believe I have to find the the third angle for the triangle:

a, (a + 80)

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

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**Complementary Angles: ** Pair of angles whose sum is 90[sup]o[/sup].

**Supplementary Angles: ** Pair of angles whose sum is 180[sup]o[/sup].

Example - Find the complementary angle of 53

Let the required angle be x

Therefore, x + 53 = 90

==> x = 90 - 53 = 37

Thus, the required complementary angle of 53 is 37

Example - Find the supplementary angle of 53

Let the required angle be x

Therefore, x + 53 = 180

==> x = 180 - 53 = 127

Thus, the required supplementary angle of 53 is 127

The complimentary angle of a is 90 - a

The supplementary angle of a is 180 - a

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,273

hi demha

I assume these are supplementary angles.

1. 87 - I said C

A 77

B24

C93

D47

E 31

F 48

correct

2. 160 - I said A

A 10

B20

C30

D40

E 50

F 60

160 + 10 is not 180

3. 68 - I said E

A 851

B295

C302

D574

E 112

F 638

correct

4. 174 - I said D

A 3

B4

C5

D 6

E 7

F 8

correct

5. a - Not sure how to solve, need help

A 180-a

B180/2

C 179*a

D 179+a

E 60

F pi

a plus something makes 180. Which of these answers fits the something?

Find the complementary angles of the following.

6. 53 - I said F

A 90

B32

C 25

D 45

E 18

F 37

correct

7. 12 - I said B

A 46

B78

C98

D31

E 52

F 64

correct

8. 73.5 - I said A

A 16.5

B34.2

C29.4

D17.7

E 57.9

F 11.3

correct

9. 23.7 - I said A

A 66.3

B70.1

C42.5

D83.9

E 54.8

F 36.2

correct

10. a - Also not sure how to solve this one

A 90/a

Ba-90

Ca/2

D90-a

E 90-2

F a^2

Similar to Q5. This time you want a plus something makes 90.

---

I could also use some help understanding how to solve this. I believe I have to find the the third angle for the triangle:

a, (a + 80)

Angles must add to 180.

So angle 1 plus angle 2 plus angle 3 = 180 => angle 3 = 180 -(angle 1 plus angle 2)

angle 3 = 180 - (a + a + 80)

Can you simplify the algebra from here?

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**demha****Member**- Registered: 2012-11-25
- Posts: 195

Hi Bob,

I sent in my lesson and got all of them but #2 right. I sent in #2 and said the answer was B, 20. I got a 10 on my lesson!

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,273

OK, good news! Thanks for letting me know.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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