Tangents

Question 1

What is a normal line?

Answer 1

It’s a line that’s perpendicular to the tangent line located at the point of contact.

Question 2

How do you construct an external straight-line tangent between 2 circles?

Answer 2

• Draw a big and small circle close by but separately.
• Join centre point and other point with a line.
• Bisected line.
• From middle of line, draw semi-circle connecting both points.
• Take away the smaller circle’s radius from the bigger circle’s.
• From the bigger circle’s circumference, take your answer and draw a circle inside of the bigger circle.
• Draw a normal line.
• Draw a parallel line at P.O.C
• Connect both P.O.C’s

Question 3

How do you construct an internal straight-line tangent between 2 circles?

Answer 3

• Follow points 1- 4 from external line tangent.
• Add big circle radius and small circle radius.
• Take your answer and draw bigger circle around big circle.
• Draw normal line.
• Draw a parallel line to normal line.
• Draw a line connecting both P.O.C’s.

Question 4

How do you make a tangent arc to 2 external circles?

Answer 4

• Locate the centre point by scribing an arc from both circles.
• The length of the arc will be the radius of the tangent arc added to the individual circle’s radius.
• Where the 2 arcs cross the centre of the tangent arc.
• Join the centres of the circles to the centre of the tangent arc to locate the P.O.C’s.
• Scribe the tangent arc between the 2 P.O.C’s.

Question 5

How do you make a tangent arc to 2 internal circles?

Answer 5

• Locate the centre point by scribing an arc from both circles.
• The length of the arc will be the radius of the individual circle’s subtracted from the tangent arcs radius.
• Where the 2 arcs cross is the centre of the tangent arc.
• Join the centres of the circles to the centre of the tangent arc and extend to the circumference of the circles to locate the POC’s.
• Scribe the tangent arc between the 2 points of contact.

Question 6

How do you make a tangent arc with 1 internal and 1 external circle?

Answer 6

• Locate the centre point by scribing an arc from both circles.
• For the external tangent, add the radius of the tangent to the radius of the circle.
• For the internal tangent, subtract the radius of the circle from the tangent radius.
• Where the 2 arcs cross is the centre of the tangent arc.
• Join the centre of the external circle to the tangent arc to locate the point of contact.
• Scribe the tangent arc between the 2 points of contact.