Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Whoops! Where did 'y' spring from ? I hope you mean x + x - 35 = 90.

Bob

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

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

yup I mean x

So x is the large than the small angle is x-35

So x+x-35=90

x+x= 2x

-35+2x=90

-(-35) -(-35)

2x=125

x = 62.5

So the measure of the larger angle is 62.5

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Yes. In the question post (#23) you had 62.2 I assume a typo.

Bob

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

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

yeah its a typo

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I choose D because I didn't read the question correctly ammm but can I use the distance formula to get the answer ?

3. In the figure shown, line segment AC = CE , D is the midpoint of CE , DE=5, and BC=2 . What is the measure of AB ?

A 5

B7

C8

D10

One, who adopts patience, will never be deprived of success though it may take a long time to reach him. Imam ali (as)<3

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

hi zee-f

I've re-made the diagram with two extras: (i) I've put on the given distances; (ii) I've put a pointer to the midpoints.

You see, if AC = CE, then C is the midpoint of AE, and D is the midpoint of CE.

So start with DE = 5, and work out CE. From that answer work out AC.

Then use BC = 2 to finish the problem.

Bob

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

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

DE = 5 and I know that DE is half of CE So CE would equal CD*2 So CE=10

DE=5

CD=5

CE= 10

AC= 10

So AE= 20

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

If I say the distance from B to c is 2

then AB would be 10-2=8

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Correct. Well done.

Did you find my diagram helpful?

When I get one of your questions, the first thing I do is to make a diagram to show the problem.

Give it a try.

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

Yeah I sure did I drew it on my note book then found out how easy the question was I sure will try it next time

I corrected the following :

I choose D and it was incorrect

now I choose C

because adjacent angles are supplementary

AD = EH

FG=BC

So A= x

b = 180 - x

So D is X F= 180-x

So the angles are supplementary because they add up to 180

4. Which statement about angle 1 and 2 must be true?

A angle 1 is congruent to angle 2

B- 1 is the complement of angle 2

C- angle 1 is the supplement of angle 2

D- Angle 1 and 2 are vertical angles

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

C is correct.

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I choose A and it was incorrect still confused

Ok so Obtuse Triangle has an angle that is more than 90° So that means only one angle is more than 90° and an isosceles triangle has two equal sides and two equal angles. So am thinking the last picture

5. Which triangle is an obtuse isosceles triangle?

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Correct!

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

Ok first I choose B

My correction is :

area = (½)(apothem)(perimeter)

1/2 * 3.8 * 48 = 91.2

6. Calculate the area of the regular octagon shown.

A 21.9 square meters

B48.0 square meters

C91.2 square meters

D350.4 square meters

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I need help solving this I choose D and it was incorrect

11. Which is the contrapositive of the following statement? If quadrilateral ABCD is a rectangle, then quadrilateral ABCD is a square.

A If quadrilateral ABCD is a square, then quadrilateral ABCD is a rectangle.

B If quadrilateral ABCD is not a square, then quadrilateral ABCD is not a rectangle.

C If quadrilateral ABCD is not a rectangle, then quadrilateral ABCD is not a square.

D If quadrilateral ABCD is not a square, then quadrilateral ABCD is a rectangle.

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

hi zee-f

Q6. 91.2 That's what I get too.

Q11. Structure for a contrapositive:

If <statement A>, then <statement B> becomes if <NOT statement B>, then <NOT statement A>.

So both statements collect a NOT, and the order of statements is reversed.

The two versions are logically the same; because if B is NOT true, then A cannot be either (as A true implies B true).

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

So A would be correct?

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

A ? Where are the NOTs ?

If <statement A>, then <statement B> becomes if <**NOT** statement B>, then <**NOT** statement A>.

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I thought you meant reverse the statements

So B is the answer

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

B is my answer too.

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

8. Select which statement is true about the relationship between the measures of angle A and angle B in the diagram shown.

A The measure of angle A is greater than the measure of angle B .

B The measure of angle B is greater than the measure of angle A.

C The measure of angle A is equal to the measure of angle B .

D Cannot be determined without any other calculations.

#8- Ok so I first choose B but I still see that my answer is correct

because the measure of the missing angle would 2.38

Then I use cosine= A/H

9/11 = 0.82

cos-¹ = 34.92

So that is angle A

90+34.92=124.92

So angle B = 180 - 124.92 = 55.08

A= 34.92

B= 55.08

C= 90

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Yes, that's ok.

My method was different but gets the same answer.

Bob

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

So what I did isn't incorrect right? but I answered B and it was incorrect

Offline

**zee-f****Member**- Registered: 2011-05-12
- Posts: 1,220

I choose B and it was incorrect still cant find the answer

16. A right circular cylinder has a base diameter of 12 meters and a height of 16 meters. What is the approximate total lateral surface area of the cylinder?

A 602.9 m²

B 829.4 m²

C 1507.2 m²

D 2034.7 m²

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,259

Q8. Sorry. B is correct. What I was trying to say is you could have got to the answer more quickly.

But it doesn't matter. Correct is correct however you get there.

Q16. Not B.

You need to imagine the curved surface 'unwrapped' so that you have a rectangle.

height = 16 length = circumference of the circle = pi times D area = height x circumference.

http://www.youtube.com/watch?v=gi7aaZ87EoQ

Bob

Offline