ABC is a right triangle and E a point in the plane. Construct with compass and ruler the equilateral triangle EDF with D and F lying in the sides of ABC.
2026-04-19 11:49:53.1776599393
construction proplem-solved pending proof
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This is a complete new version.
We have to assume that E is outside of ABC and within range. Let ABC be right-angled at B.
Draw the equilateral triangle PBE.
Construct the circum-circle PBE cutting BC at X.
PX will cut AC at D.
Construct the circle (centered at E with ED as radius) cutting BC at F.
This is because if $\triangle PED \cong \triangle BEF, \angle DEF = \angle PEB = 60^0$