Isosceles Right Triangle: Quick Investigation

Isosceles Right Triangle: Quick Investigation
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2017-08-28 22:45
This interactive GeoGebra example dynamically demonstrates the properties of an isosceles right triangle and its connection to sine and cosine function graphs. Core mathematical concepts include the side-angle relationships in an isosceles right triangle, definitions of sine and cosine in right triangles, the orthocenter's position, and function graph plotting. Construction highlights: using GeoGebra commands such as Sequence, Segment, Circle, OrthogonalLine, Intersect, Dilate, Rotate, Angle, and Polygon, the construction involves points B, A, C, G', J' and objects like lines g, h, i, k, l and circles, creating the triangle through rotations, dilations, and perpendicular lines, with angle α measured via the Angle command. Suitable for middle or high school classrooms or self-study, this activity helps explore triangle properties, trigonometric functions, and geometric construction, fostering dynamic mathematical investigation.

GeoGebra Commands & Parameters

  1. Sequence(Rotate[(1, 0), i°, (0, 0)], i, 15, 360, 15) → list1
  2. Segment(B, A) → g
  3. Circle(B, A) → h
  4. OrthogonalLine(B, g) → i
  5. Intersect(h, i) → I, J
  6. Dilate(B, If[0 < j ≤ 1, 1 - j, 0], A) → G'
  7. Segment(B, G') → k
  8. Rotate(B, If[1 < j ≤ 2, ((j - 1) * pi / 2), pi / 2], B) → G'_1
  9. Rotate(G', If[1 < j ≤ 2, ((j - 1) * pi / 2), pi / 2], B) → C
  10. Segment(G'_1, C) → k'
  11. Angle(A, B, C) → α
  12. Dilate(J, If[2 < j ≤ 3, 3 - j, 0], A) → J'
  13. Segment(J, J') → l
  14. Polygon(B, A, J) → poly2, j_1, g_1, h_1