How do you construct 150 degree angle using compasses?

Answer 1

You also need a straight edge.

Because of the poor graphic facility of this browser, the description is rather longer and sounds more complicated than it is.

In summary, you

• draw a 60 degree angle,
• bisect it, and then
• consider its supplement.

So here goes (it will be easier if you read and do it together).:

• Draw a straight line.
• Mark a point A on the line.
• With the compasses, draw a quarter circle arc that intersects the line at point B.
• Using the same compass setting, draw another large arc from B which intersects the first arc at point C (angle CAB will be 60 degrees).
• With the compass point now at C, and still using the same compass setting, draw another arc to intersect the last arc at D.
• Angle DAB is 30 degrees.
• If BA is extended (on the other side of A) to a point E, the angle DAE is 150 degrees.

You also need a straight edge.

Because of the poor graphic facility of this browser, the description is rather longer and sounds more complicated than it is.

In summary, you

• draw a 60 degree angle,
• bisect it, and then
• consider its supplement.

So here goes (it will be easier if you read and do it together).:

• Draw a straight line.
• Mark a point A on the line.
• With the compasses, draw a quarter circle arc that intersects the line at point B.
• Using the same compass setting, draw another large arc from B which intersects the first arc at point C (angle CAB will be 60 degrees).
• With the compass point now at C, and still using the same compass setting, draw another arc to intersect the last arc at D.
• Angle DAB is 30 degrees.
• If BA is extended (on the other side of A) to a point E, the angle DAE is 150 degrees.

You also need a straight edge.

Because of the poor graphic facility of this browser, the description is rather longer and sounds more complicated than it is.

In summary, you

• draw a 60 degree angle,
• bisect it, and then
• consider its supplement.

So here goes (it will be easier if you read and do it together).:

• Draw a straight line.
• Mark a point A on the line.
• With the compasses, draw a quarter circle arc that intersects the line at point B.
• Using the same compass setting, draw another large arc from B which intersects the first arc at point C (angle CAB will be 60 degrees).
• With the compass point now at C, and still using the same compass setting, draw another arc to intersect the last arc at D.
• Angle DAB is 30 degrees.
• If BA is extended (on the other side of A) to a point E, the angle DAE is 150 degrees.

You also need a straight edge.

Because of the poor graphic facility of this browser, the description is rather longer and sounds more complicated than it is.

In summary, you

• draw a 60 degree angle,
• bisect it, and then
• consider its supplement.

So here goes (it will be easier if you read and do it together).:

• Draw a straight line.
• Mark a point A on the line.
• With the compasses, draw a quarter circle arc that intersects the line at point B.
• Using the same compass setting, draw another large arc from B which intersects the first arc at point C (angle CAB will be 60 degrees).
• With the compass point now at C, and still using the same compass setting, draw another arc to intersect the last arc at D.
• Angle DAB is 30 degrees.
• If BA is extended (on the other side of A) to a point E, the angle DAE is 150 degrees.

Answer 2

You also need a straight edge.

Because of the poor graphic facility of this browser, the description is rather longer and sounds more complicated than it is.

In summary, you

• draw a 60 degree angle,
• bisect it, and then
• consider its supplement.

So here goes (it will be easier if you read and do it together).:

• Draw a straight line.
• Mark a point A on the line.
• With the compasses, draw a quarter circle arc that intersects the line at point B.
• Using the same compass setting, draw another large arc from B which intersects the first arc at point C (angle CAB will be 60 degrees).
• With the compass point now at C, and still using the same compass setting, draw another arc to intersect the last arc at D.
• Angle DAB is 30 degrees.
• If BA is extended (on the other side of A) to a point E, the angle DAE is 150 degrees.