Math Is Fun Forum

emmakatecumbo

Member

Registered: 2017-09-22

Posts: 35

Geometry Work

I have posted my homework down below with the answers. The teachers comment are at the bottom and I will also post a link to the diagram down below. Please help I have been stuck for a couple days and it has to be done asap.

1. Refer to the image at the right. If angle 1 is 30 degrees, and angle 5 is 70 degrees, are the two lines
parallel?
answer : No it is not parallel

2. Refer to the image at right. If angle 2 is 30 degrees and angle 4 is 60 degrees, are the lines parallel?
answer : No it is not parallel

3.  Refer to the image at right. If angle 2 and angle 6 are both 70 degrees, are the lines parallel?
answer : No it is not parallel

7. Polygon A has sides of 4, 3, 5, and 3. Polygon B has sides of 8, 6, 10, and 6. What are the two possible
scale factors here?
answer : 4 / 8 = 1/2
3 / 6 = 1/2
5 / 10 = 1/2
3 / 6 = 1/2 <-- this is my answer and its correct but I am suppose to find the other scale factor. what is it?

10.  A right triangle has a 90 degree angle, and an angle x. What will the measure of the third angle be?
answer : 90 = x

Teacher Comments :

#1    Correct, but how can you tell?

#2     Right, but again, how do you know?

#3     These ARE parallel... how do we know?

#7    Incorrect... show me how you would set these up to find the scale factors

#10    What is the sum of all angles?   How many do you know?  Subtract EVERYTHING you are given from the SUM of all... then simplify by combining like terms

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Geometry Work

#1    Correct, but how can you tell?

#2     Right, but again, how do you know?

#3     These ARE parallel... how do we know?

#7    Incorrect... show me how you would set these up to find the scale factors

#10    What is the sum of all angles?   How many do you know?  Subtract EVERYTHING you are given from the SUM of all... then simplify by combining like terms

If the angles are equal you have an example of 'corresponding angles' http://www.mathsisfun.com/geometry/corr … ngles.html

(7) is NOT incorrect!  Your working is exactly what is needed.  I'm guessing that your teacher is also expecting that you do (polygon B):polygon A, which would 'invert' the scale factor.  So I would try x2 as the second answer.

(1) is also correct but you have an equals sign = where you need a minus sign -  Looks like you just pressed the next door key on your computer.

I suspect that your answers are marked by a robot rather than a human.  So, unless you get exactly what the robot has in its answer store, it gets marked wrong.  I'd hope that the 'teacher' would sort this out and use some common sense, but it doesn't seem to have happened here.  Maybe the teacher is not as good at math as you are

Hope this helps.

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
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

emmakatecumbo

Member

Registered: 2017-09-22

Posts: 35

Re: Geometry Work

I got number 7 and 10 correct now the teacher said

#1, 2, 3    you need to state the angle relationship.... corresponding, alternate interior, same side interior.. etc.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Geometry Work

Have you read my post?  I have answered this above and given a link to the MIF page on this.

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
Sometimes I deliberately make mistakes, just to test you!  …………….Bob