Right angle trigonometry homework question

AI Thread Summary
The problem involves finding the coordinates of two holes drilled in a steel plate shaped like one-fourth of a circle with a 60 cm radius. The solution manual indicates that the hypotenuse of the relevant right triangle is 56 cm, which represents the radial distance from the center of the circle to the holes. The holes are positioned at angles of 30° and 60° from the horizontal edge. Understanding that the hypotenuse is a radial measurement clarifies the approach to solving for the rectangular coordinates of the holes. This insight allows for the application of trigonometric functions to determine the coordinates accurately.
xxwinexx
Messages
7
Reaction score
0

Homework Statement


A steel plate has the form of one-fourth of a circle with a radius of 60 centimeters. Two two-centimeter holes are to be drilled in the plate positioned as shown in the figure. Find the coordinates of the center of each hole.

Homework Equations


I know it's got to be a simple sin/cos right angle equation, but I've no clue how they came about to getting the 56 centimeter measurement to be the hypotenuse on the solution that I have in my manual.

The Attempt at a Solution



I attempted drawing a few right angle triangles that I thought would work, but nothing came from it. If someone could explain how the solution manual was able to get a triangle with 56 as the hypotenuse, I would be able to move forward from there.

I've attached both the image of the problem, and the image of the first part of the solution worked out.
 

Attachments

  • Screen Shot 2012-11-28 at 3.24.39 PM.png
    Screen Shot 2012-11-28 at 3.24.39 PM.png
    46.6 KB · Views: 4,336
  • Screen Shot 2012-11-28 at 3.23.23 PM.png
    Screen Shot 2012-11-28 at 3.23.23 PM.png
    11.2 KB · Views: 4,980
Last edited:
Physics news on Phys.org
for the first hole you have a 30-60-90 rt triangle with hyp 56 so you should be able to compute the x1 and y1

similarly for the x2 y2
 
It's because it's the radius of the circle. Every hypotenuse along the circumference of a circle that is measured from the centre is going to be the radius of the circle.
 
xxwinexx said:

Homework Statement


A steel plate has the form of one-fourth of a circle with a radius of 60 centimeters. Two two-centimeter holes are to be drilled in the plate positioned as shown in the figure. Find the coordinates of the center of each hole.


Homework Equations


I know it's got to be a simple sin/cos right angle equation, but I've no clue how they came about to getting the 56 centimeter measurement to be the hypotenuse on the solution that I have in my manual.
It looks to me like the two drilled holes are a radial distance of 56 cm from the center, and at angles of 30° and 60° from the horizontal edge.

These values aren't calculated - they're part of the given information in the problem. The positions of the two holes are essentially in polar coordinates, and your job is to find the rectangular coordinates of the holes.
xxwinexx said:

The Attempt at a Solution



I attempted drawing a few right angle triangles that I thought would work, but nothing came from it. If someone could explain how the solution manual was able to get a triangle with 56 as the hypotenuse, I would be able to move forward from there.

I've attached both the image of the problem, and the image of the first part of the solution worked out.
 
jedishrfu said:
for the first hole you have a 30-60-90 rt triangle with hyp 56 so you should be able to compute the x1 and y1

similarly for the x2 y2

Right, that's basically what the solution is saying, I guess I just can't see how they figured that right triangle/hypotenuse out..

Edit: Ohhhh...I wasn't thinking of the 56 as a radial measurement. I feel really dumb now. Thanks guys!
 
I tried to combine those 2 formulas but it didn't work. I tried using another case where there are 2 red balls and 2 blue balls only so when combining the formula I got ##\frac{(4-1)!}{2!2!}=\frac{3}{2}## which does not make sense. Is there any formula to calculate cyclic permutation of identical objects or I have to do it by listing all the possibilities? Thanks
Back
Top