Proposition 17
Construction
From a given point outside of a given circle to draw a line tangent to the circle.
Construction Steps
1. Let the circle through the point D centered at O be the given circle and P be the given point outside of the circle.
2. JoinOP and let its intersection with the circle be C.
3. Construct the circle through the point P centered at O.
4. Construct a line that is perpendicular toOP at C and intersecting the circle through the point P at A.
5. JoinOA and let B be its intersection with the original circle. Join PB . From the given point P, the line PB has been drawn tangent to the given circle.
2. Join
3. Construct the circle through the point P centered at O.
4. Construct a line that is perpendicular to
5. Join
Original statement
ἀπὸ τοῦ δοθέντος σημϵίου τοῦ δοθέντος κύκλου ἐϕαπτομένην ϵὐθϵῖαν γραμμὴν ἀγαγϵῖν.
English translation
From a given point to draw a straight line touching a given circle.
