Ducky101

If anyone have the green ACT booklet that the school gives out and can help me with these problems would be great.

# 37, 41, 50, 52, and 53. Most of the problems has picture which is why I didn't posted up the question

cowking15

Thats really vague, Use paint and the drawing tools to make the pictures and write up the questions, then itll be much easier for you to get help.

Ducky101

37. As shown in the standard (x,y) coordinate plane below, P(6,6) lies on the circle with center (2,3) and the radius 5 coordinate units. What are the coordinates of the image of P after the circle is rotated 90 degree clockwise about the center of the circle.

A(2,3) B(3,2) C (5,-1) D(6,0) E (7,3)
http://img204.imageshack.us/img204/1849/87328288.png

45daysinrome

What's the answer?

45daysinrome

I'm assuming that your sketch is drawn like in the problem. So when you rotating the circle 90 degrees upon (2,3), it seems as though P is the fourth quadrant which has the coordinates (x, -y). C is the only one that's like that.
Also, A and B just don't make sense.
Please correct me if I'm wrong.

Adude1192

You're right C is the correct answer.

Ducky101

Yes C is the correct answer ,but the different between C and D are so close -1 and 0. I did not know whether 90 degree would pass the x-axis or not...It seem like an estimating problem???
Anyone else>???

45daysinrome

Estimating would be the easiest way to go about doing this problem.
You could, however, try to make a right triangle and find the distances but that's just too much work. I don't know if its worth the time, or if it is even feasible.

cowking15

^ That's what I went ahead and did, it turned into an AP Algebra problem. Estimating is the way to go

Ducky101

cowking15: If you dont mind can you show me the math way to do this problem?

TheMasterofAct

Does that green book have an exam number, like 61d, 58b, etc.? I got a few exams from teachers but they did not come in a green book, might be able to help you out...

Ducky101

ACT-64E practice

cowking15

Ducky,

I didnt wanna fully work it out but this is the process. Since when rotation an point, the distance from the center stays the same to the point right? SO you know that the distance from the center to the point equals the distance from the center to the new point

you use the center coordinates 2,3 the orig coors 6,6 and the new coords x,y to solve it.
It gets pretty hectic

Shehab

You could solve this problem in an easy way like the following :
1-Draw a line from the point (6,6) to the other side of the circle witch will make a 180 degree.
2- Because the circle is rotated clockwise you will draw a line from the midpoint of the line"vertical line 90 degree" you draw in step one and will go in the other side of the circle witch is toward the clock rotate.
3-when you connect the second line with the circle you will find that the circle is mating with the line in the point (5,-1).