Counter
Mathematics Dictionary
Dr. K. G. Shih

Figures


  • Q01 | - F101 : Sides AB, AC and Median AD are given
  • Q02 | - F102 : Medians AD, AE and side AB are given
  • Q03 | - F103 : Three circles touch each other with same common tangent
  • Q04 | - F104 : Square side a and Four sim-circle radius a/2
  • Q05 | - F105 : Circle inscribed an equilateral triangle with other two small circle
  • Q06 | - F106 : Circle inscribed an equilateral triangle with other 3 small circles
  • Q07 | - F107 : Square and equaliteral triangle
  • Q08 | - F108 : Area of triangle formed by medians of triangle ABC
  • Q09 | - F109 : Heights and medians of equilateral triangle ABC
  • Q10 | - F110 : Pedal triangle of equilateral triangle
  • Q11 | - F111 : Excentral triangle of equilateral triangle
  • Q12 | - F112 : Pedal triangle of triangle ABC
  • Q13 | - F113 : Ex-central triangle of triangle ABC
  • Q14 | - F114 : Construct 4 congruent triangles using triangle ABC
  • Q15 | - F115 : Ortho-center, centroid and circum-center are colinear
  • Q16 | - F116 : Prove cos(A - B) = cos(A)*cos(B) + sin(A)*sin(B)
  • Q17 | - F117 : Divide equilateral triangle side into 3 eqal parts
  • Q18 | - F118 : Point inside equilaleral triangle to sides equal height
  • Q19 | - F119 : A(7,4), B(3,1), C(0,k) find k if AC + BC is minimum
  • Q20 | - F120 : Hexagon inscribed equilateral triangle
  • Q21 | - F121 : Heights of triangle are concurrent
  • Q22 | - F122 : Bisector of a line
  • Q23 | - F123 : Bisector of an angle
  • Q24 | - F124 : Conditions of two lines in parallel
  • Q25 | - F125 : Angles in a circle
  • Q26 | - F126 : Trinagle sides s = (a + b + c)/2
  • Q27 | - F127 : Circum-center
  • Q28 | - F128 : In-center
  • Q29 | - F129 : Ex-center
  • Q30 | - F130 : Centroid
  • Q31 | - F131 : Ortho-center
  • Q32 | - F132 : Pedal Triangle
  • Q33 | - F133 : Ex-central triangle
  • Q34 | - F134 : Three point define a circle
  • Q35 | - F135 : Tangent to circle (1)
  • Q36 | - F136 : Tangent to circle (2)
  • Q37 | - F137 : Concyclic
  • Q38 | - F138 : How many chords
  • Q39 | - F139 : Centroid
  • Q40 | - F140 : Locus in paralleldiagram
  • Q41 | - Locus of five centers of triangle

  • Answers


    Q01. Figure 101 : Sides AB, AC and Median AD are given

    Construct triangle ABC

    Go to Begin

    Q02. Figure 102 : Medians AD, AE and side AB are given

    Construct triangle ABC

    Go to Begin

    Q03. Figure 103 : Three circles touch each other with same common tangent

    Find area of small circle

    Go to Begin

    Q04. Figure 104 : Square side a and Four sim-circle radius a/2

    Find area of shaded portion

    Go to Begin

    Q05. Figure 105 : Circle inscribed an equilateral triangle with other 2 small circles

    Find area of the smaller circle

    Go to Begin

    Q06. Figure 106 : Circle inscribed an equilateral triangle with other 3 small circles

    Find area of the smaller circles

    Go to Begin

    Q07. Figure 107 : Square and equaliteral triangle


    Go to Begin

    Q08. Figure 108 : Area of triangle formed by medians of triangle ABC

    Note
    • We should remeber the 1/3 rule
    • This diagram is also used to prove that medians are concurrent

    Go to Begin

    Q09. Figure 109 : Heights and medians of equilateal triangle ABC

    Heights are concurrent

    Go to Begin

    Q10. Figure 110 : Pedal triangle of equilateral triangle ABC

    Construct a pedal triangle

    Go to Begin

    Q11. Figure 111 : Ex-central triangle of equilateral triangle

    Construct ex-central triangle

    Go to Begin

    Q12. Figure 112 : Pedal triangle of triangle ABC

    Construct Pedal triangle

    Go to Begin

    Q13. Figure 113 : Ex-central triangle of triangle ABC

    Construct ex-central triangle

    Go to Begin

    Q14. Figure 114 : Construct 4 congruent triangles using triangle ABC

    Reference

    Go to Begin

    Q15. Figure 115 : Ortho-center, centroid and circum-center are colinear

    Reference

    Go to Begin

    Q16. Figure 116 : cos(A - B) = cos(A)*cos(B) - sin(A)*sin(B)

    Proof

    Go to Begin

    Q17. Figure 117 : Divide equilateral triangle side into 3 eqal parts

    Proof

    Go to Begin

    Q18. Figure 118 : Point inside equilaleral triangle to sides equal height

    Proof

    Go to Begin

    Q19. Figure 119 : A(7,4), B(3,1), C(0,k) find k if AC + BC is minimum

    Proof

    Go to Begin

    Q20. Figure 120 : Hexagon inscribed equilateral triangle

    Reference

    Go to Begin

    Q21. Figure 121: Heights are concurrent

    Proof

    Go to Begin

    Q22. Figure 122 : Bisector of a line

    Diagram
    Method

    Go to Begin

    Q23. Figure 123 : Bisector of an angle

    Diagram
    Method

    Go to Begin

    Q24. Figure 124 : Conditions of two parallel lines

    Diagram
    Method

    Go to Begin

    Q25. Figure 125 : Angles in circle

    Diagram
    Method

    Go to Begin

    Q26. F126 : Trinagle sides s = (a + b + c)/2

    Diagram
    Application : See keywords
    • 1. Area of triangle = Sqr(s*(s-1)*(s-b)*(s-c))
    • 2. In-circle : Tangent at A is (s - a)
    • 3. Ex-circle : Tangent at A is s
    • 4. Half angle formula in terms of s

    Go to Begin

    Q27. F127 : Circum-center

    Diagram
    Reference
    • GE 02 05
    • GE 03 02

    Go to Begin

    Q28. F128 : In-center

    Diagram
    Reference
    • GE 02 06
    • GE 03 02

    Go to Begin

    Q29. F129 : Ex-center

    Diagram
    Reference
    • GE 04 08

    Go to Begin

    Q30. F130 : Centroid

    Diagram
    Reference
    • GE 02 07
    • GE 03 02

    Go to Begin

    Q31. F131 : Ortho-center

    Diagram
    Reference
    • GE 02 08
    • GE 03 02

    Go to Begin

    Q32. F132 : Pedal triangle

    Diagram
    Reference
    • GE 03 04
    • See F112

    Go to Begin

    Q33. F133 : Ex-central triangle

    Diagram
    Reference
    • See F113

    Go to Begin

    Q34 F134 : Three points define a circle

    Diagram
    Reference
    • GE 04 03

    Go to Begin

    Q35. F135 : Tangent to circle (1)

    Diagram
    Reference
    • GE 04 02

    Go to Begin

    Q36. F136 : Tangent to circle (2)

    Diagram
    Reference
    • GE 04 02

    Go to Begin

    Q37. F137 : Concyclic

    Diagram
    Reference

    Go to Begin

    Q38. F138 : How many chords ?

    Diagram
    Reference
    • GE 04 05

    Go to Begin

    Q39. F139 : Circile inscribed in quadrilateral

    Diagram
    Reference
    • GE 04 06 and GE 04 07

    Go to Begin

    Q40. Q40 : Locus in parallelogram

    Question
    • Parallelogram ABCD
    • Bisectors of angle BCD and angle ADC meet at O
    • Find locus of O
    Diagram
    Diagram

    Go to Begin

    Q41 : Locus of five centers of triangle

    Diagram

    Go to Begin

    Show Room of MD2002 Contact Dr. Shih Math Examples Room

    Copyright © Dr. K. G. Shih, Nova Scotia, Canada.

    1