
Geometry Geometry Math Forum 
 LinkBack  Thread Tools  Display Modes 
March 30th, 2016, 03:44 AM  #1 
Newbie Joined: Mar 2016 From: Brisbane, Australia Posts: 2 Thanks: 0  Calculate coordinates of embedded rectangle on rotation of parent rectangle
OK... too many years since school but I want to know the mathematical formulae to calulcate the coordinates of the green rectangle (X,Y of each corner) when he known values are: Width and Height of parent (blue) rectangle Rotation in degrees or radians about the centre of the rectangle Initial coordinates of the small rectangle are relative to the larger one e.g. Blue is 2000 x 1500 pixels (points) Top Left is 0,0 Bottom right is 2000,1500 in an X,Y coordinate system Green has four corners defined where each has a defined X,Y coordinate. I can work with a formulae relating to distances in mm instead of pixels, and angles; and can convert them. Note; I need to know the change in location (A > B) of each corner in relation to either the Centre (D), or the original 0,0 (C) Hope someone can help : ) 
March 30th, 2016, 05:49 AM  #2 
Newbie Joined: Feb 2016 From: israel Posts: 17 Thanks: 3 
iv'e attached an example for point A. you can do the same for each point i'm assuming that both triangles rotate together 
March 30th, 2016, 05:54 AM  #3 
Newbie Joined: Feb 2016 From: israel Posts: 17 Thanks: 3 
important note: this Matrix is for counter clockwise revolution. for clockwise use a negative angle

March 30th, 2016, 07:19 AM  #4 
Math Team Joined: Jul 2011 From: Texas Posts: 3,002 Thanks: 1587  
March 30th, 2016, 12:48 PM  #5 
Newbie Joined: Mar 2016 From: Brisbane, Australia Posts: 2 Thanks: 0 
Perfect! I'd forgotten about Matrices. Thankyou both : ) especially Shai for the old school penmanship


Tags 
calculate, coordinates, embedded, parent, rectangle, rotation 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Greatest rectangle of given ratios from a fixed rectangle  givera  Geometry  4  October 17th, 2015 02:10 PM 
Calculate the length and width of a rectangle  Apple30  Geometry  8  June 24th, 2015 09:18 PM 
Rotation of Cartesian Coordinates around an Axis problem?  Fraizerangus  Linear Algebra  1  August 9th, 2011 06:25 AM 
How to calc sides of rectangle inside a rotated rectangle  mhurkman  Algebra  4  February 7th, 2011 10:40 AM 
Get bounding box of rectangle after rotation  Bakunph  Algebra  2  November 5th, 2009 06:18 PM 