Thursday, June 9, 2011

Problem 619: Triangle Area, 30 Degrees, Incircle, Incenter, Tangent

Geometry Problem
Level: Mathematics Education, High School, Honors Geometry, College.

Click the figure below to see the complete problem 619.

 Problem 619: Triangle Area, 30 Degrees, Incircle, Incenter, Tangent

1 comment:

  1. a=BC=5+2=7
    5=BD=s-b, 2=DC=s-c
    ∆=√[s(s-a)(s-b)(s-c)]
    =√[s(s-a).5.2]
    =√10.√[s(s-a)]
    tan(A/2)=√[(s-b)(s-c)/s(s-a)]=√10/√[s(s-a)]
    Multiplying respective sides:
    ∆ tan(A/2)=10
    ∆=10.cot15°=10(2+√3)sq units

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