Properties of Cyclic Quadrilaterals
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This GeoGebra applet demonstrates a direct corollary of the inscribed angle theorem: in any cyclic quadrilateral, opposite angles are supplementary. The applet involves concepts of circles, angles, and polygons. Using GeoGebra commands such as Circle, Point, Rotate, CircleArc, Segment, Intersect, CircleSector, Dilate, Vector, Translate, Angle, Ray, and Polygon, students can visually understand the properties of cyclic quadrilaterals. Suitable for students in middle school and above for geometric construction.
GeoGebra Commands & Parameters
Circle(A, B) → cPoint(c) → CRotate(C, 2°, A) → C'CircleArc(A, C', C) → dPoint(d) → DCircleArc(A, D, C) → ePoint(e) → ECircleArc(A, E, C) → fPoint(f) → FCircleArc(A, F, C) → gPoint(g) → GSegment(D, E) → bSegment(E, F) → hSegment(D, G) → aSegment(G, F) → iCircle(F, (0.2 * Distance[A, B])) → kCircle(E, (0.2 * Distance[A, B])) → pCircle(G, (0.2 * Distance[A, B])) → qCircle(D, (0.2 * Distance[A, B])) → rIntersect(k, i, 1) → HIntersect(k, h, 1) → IIntersect(p, h, 1) → JIntersect(p, b, 1) → KIntersect(r, a, 1) → LIntersect(r, b, 1) → MIntersect(q, a, 1) → NIntersect(q, i, 1) → OCircleSector(G, N, O) → sCircleSector(F, H, I) → tCircleSector(E, J, K) → c_1CircleSector(D, M, L) → d_1Circle(A, B) → e_1Dilate(E, If[0 < j ≤ 1, 1 - j, 0], G) → E'Vector(E, E') → uTranslate(c_1, u) → f_1CircleArc(E, J, K) → g_1Translate(J, u) → J'Angle(O, G, J') → αRotate(f_1, If[1 < j ≤ 2, ((-(j - 1)) * α), (-α)], G) → h_1Ray(D, G) → lPoint(l) → PRay(G, P) → mDilate(F, If[2 < j ≤ 3, 3 - j, 0], D) → F'Vector(F, F') → vRay(G, D) → nPoint(n) → QRay(D, Q) → a_1Translate(t, v) → t'CircleArc(F, H, I) → k_1Translate(I, v) → I'Angle(I', D, M) → βRotate(t', If[3 < j ≤ 4, ((j - 3) * β), β], D) → t''Polygon(G, D, E, F) → poly1, g_2, d_2, e_2, f_2