F.1~F.2的Abbreviation

Congruent triangles:
(S.S.S.) (S.A.S.) (A.A.S) (A.S.A.) (R.H.S)
(corr. sides, △s) (corr.∠s, △s) (common side)

Similar triangles:
(A.A.A.) (ratio of 2 sides, inc.∠s) (3 sides prop.)
(corr. sides, ~△s) (corr.∠s, ~△s) (common ∠)

Isosceles triangles:
(base ∠s, isos. △s) (sides opp. equal ∠s)

Right-angled triangles:
(Pyth. theorem) (converse of Pyth. theorem)

Triangles:
(∠ sum of △) (ext.∠ of △) (prop. of equil.△)

Polygons:
(∠ sum of polygon) (sum of ext.∠ of polygon)

Others:
(adj.∠s on st. line) (vert. opp.∠s) (∠s at a pt.) (AB⊥CD) (given) (proved) (By construction) (intercept theorem) (mid-pt. theorem)

Parallel lines:
(corr.∠s, AB//CD) (alt.∠s, AB//CD) (int.∠s, AB//CD)
(corr.∠s equal) (alt.∠s equal) (int.∠s supp.)

Parallelograms / quadrilaterals:
(opp.∠s of //gram) (opp. sides of //gram) (diags. of //gram)
(opp. sides equal and // ) (opp. sides equal) (opp.∠s equal) (diag. bisect each other)
(property of rectangle) (property of square) (property of rhombus)

Circles:
(radii) (line from centre⊥chord bisects chord) (line joining centre to mid-pt. of chord⊥chord) (equal chords, equidistant from centre) (chord equidistant from centre are equal) (∠at centre twice ∠ at ☉ce) (∠in semi-circle) (∠s in the same segment) (equal ∠s, equal arcs) (equal ∠s, equal chords) (equal arcs, equal ∠s) (equal arcs, equal chords) (equal chords, equal arcs) (equal chords, equal ∠s) (arcs prop. to ∠s at centre) (arcs prop. to ∠s at ☉ce)

Cyclic quadrilaterals:
Uses: (opp. ∠s, cyclic quad.) (ext. ∠s, cyclic quad.)
Tests: (converse of ∠s in the same segment) (opp. ∠s supp.) (ext.∠= int. opp.∠)

Tangents:
(tangent⊥radius) (converse of tangent⊥radius)
(tangent properties)
(∠in alt. segment) (converse of ∠in alt. segment)

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