1. Principle of Geometric Construction (I) Prepared by: Asst. lecture
University Of Warith Al-anbiyaa
College of Engineering
Bio medical Engineering Department
First Class
Principle of Geometric Construction (I)
Prepared by: Asst. lecture
Karrar Al mansoori

2. Angle Triangle Radius Diameter Parallel Perpendicular Square
Geometric Symbols
Angle
Triangle
Radius
Diameter
Parallel
Perpendicular
Square
Centerline
R , r C L

3. (1) Draw the line parallel to a given line and passes through a given point+ C

4. (1) Draw the line parallel to a given line and passes through a given point+ C
Repeat

5. (2) Draw the line perpendicular to a given line at a given point
Adjacent-sides method + C

6. (2) Draw the line perpendicular to a given line at a given point
Adjacent-sides method + C
Repeat

7. (3) Draw the line perpendicular to a given line at a given point
Using Compass + C

8. (3) Draw the line perpendicular to a given line at a given point
Using Compass r2 D r2 r1 A + C
r2 > r1 B
Repeat

9. (4) Bisect a Given Straight Line AB
1. Swing two arcs of any radius greater than half-length of the line AB with the centers at the ends of the line.
2. Join the intersection points of the arcs with a line.
3. Locate the midpoint.
Given A B A B r1 r1
(not to scale)

10. (5) To Bisect an Angle Given
1. Swing an arc of any radius whose centers at the vertex.
2. Swing the arcs of any radius from the intersection points between the previous arc and the lines.
( r₂ greater than ½ r₁ )
3. Draw the line. A B C
Given A B C r1
(not to scale) r2 r2

11. Fillet and Round
Round
Sharp corner
Fillet
Round

12. Fillet and Round
To draw the arc, we must find the location of the center of that arc.
How do we find the center of the arc?

13. (6) To draw an arc of given radius tangent to two perpendicular lines
arc radius r r r

14. (6) To draw an arc of given radius tangent to two perpendicular lines
arc radius r
center of the arc
Starting point
Ending point

15. (7) To draw an arc of given radius tangent to two lines
arc radius r r r + +

16. (7) To draw an arc of given radius tangent to two lines
arc radius r
T.P.1
T.P.2

17. (8) To draw a line tangent to a circle at a point on the circle
Given C

18. (9) To draw a line tangent to a circle from a point outside the circle
Given
mark a tangent point C