Geometry Problem. Post your solution in the comment box below.
Level: Mathematics Education, High School, Honors Geometry, College.
Click the diagram below to enlarge it.
Saturday, January 31, 2015
Geometry Problem 1078: Square, Inscribed Circle, Tangent, Triangle, Area
Subscribe to:
Post Comments (Atom)
http://s13.postimg.org/z1zzlirbr/pro_1078.png
ReplyDeleteDraw lines per sketch
Triangle T1T3F similar to triangle T3CH ( case AA)
Ratio of similarity= FT3/CH=T1T3/T3C=2
So FT3=2. CH
S= ½. GT3.CH= (a+b).1/2. FT3
So S=1/4.a.(a+b)
https://docs.google.com/file/d/0Bx5WrBkYmaBHRFdEVTh4a1ExcGc/edit
ReplyDeleteComplete rectangle GCDE. Extend T3 OT1 to meet GE at H.
G,F,T1,H are concyclic.
So a(a + b) = T3F.T3G = T3T1. T3H = CD. GC = 2 CT3. GC = 4 S
Drop a perpendicular CX from C to GT3. Let CX = h
ReplyDeleteTr.s T1FT3 & CXT3 are similar right triangles. Since CT3 = T1T3/2, h = a/2
So S = h(a+b)/2 = a(a+b)/4
Sumith Peiris
Moratuwa
Sri Lanka