1. principle of geometric construction Prepared by: Asst. lecture
University Of Warith Al-anbiyaa
College of Engineering
Bio medical Engineering Department
First Class
principle of geometric construction
Prepared by: Asst. lecture
Karrar Al mansoori

2. (10) Draw an Arc Tangent to a Line and other Arc
Given line AB and arc CD
Strike arcs R1 (given radius)
Draw construction arc parallel to given arc, with center O R1
Draw construction line parallel to given line AB C D
From intersection E, draw EO to get tangent point T1, and drop perpendicular to given line to get point of tangency T2 E T1 R1 O A B
Draw tangent arc R from T1 to T2 with center E T2

3. (11) Construct a Pentagon
1- draw the circle at radius R O A
2- divided the radius of the circle at c E R
3- fix the compass at c and open it at radius AC to draw the arc AE B C G
4- fixed the compass at point A with radius AE and draw the arc intersect the circle at point B also draw the other arcs in sequences intersect the circle at points D F G D F

4. (12) Construct a Hexagon
Given distance AB across the corners, draw a circle with AB as the diameter C F D E
With A and B as centers and the same radius, draw arcs to intersect the circle at points C, D, E, and F A B
Connect the points to complete the hexagon

5. (13) Construct a Octagon 1- draw the center lines and circle
2- draw the tangent lines to the circle by using t- square and triangle which have 45 degree angle . 45 45

7. Draw circle tangent to other circle
Tangent point R1 C1 R2 C2
R1 + R2
The center of two circles and tangent point lie on the same straight line !!!

8. (14) Draw a circle tangent to two circles I+
Given + C2 + C1
Example

9. (14) Draw a circle tangent to two circles I
Given
Two circles and the radius of the third circle = R + + C2 C1

10. (14) Draw a circle tangent to two circles I
Given
Two circles and the radius of the third circle = R
R + R2
center of the arc
R + R1 R2 C R R1 + + C2 C1
Repeat

11. When circle tangent to other circle
Tangent point R1 R2 C1 C2
R2  R1
The center of two circles and tangent point must lie on the same straight line !!!

12. (15) Draw a circle tangent to two circles II+
Given + C2 + C1
Example

13. (15) Draw a circle tangent to two circles II
Given
Two circles and the radius of the third circle = R + + C2 C1

14. (15) Draw a circle tangent to two circles II
Given
Two circles and the radius of the third circle = R R R2 R1 + +
R – R2 C2 C1
R – R1 C
Repeat

15. (16) Draw a circle tangent to two circles III
Given
Two circles and the radius of the third circle = R R2 R1 + C2 + C1
R + R2
R – R1 C

19. (17) Draw an approximate ellipse
Given
Major and minor axes

20. (17) Draw an approximate ellipse
Given
Major and minor axes
Repeat

23. How to Keep Your Drawing CleanDo
Don’t

24. THANKS
FOR YOUR ATTENTION