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Question Number 42942 by Raj Singh last updated on 05/Sep/18

Answered by MJS last updated on 05/Sep/18

BC=a  CA=b  AB=c    1. a=6  β=50°  b+c=8 ⇒ c=8−b  α+γ=130° ⇒ γ=130°−α  36=b^2 +(8−b)^2 −2b(8−b)cos α  b^2 =36+(8−b)^2 −12(8−b)cos 50°  (8−b)^2 =36+b^2 −12bcos (130°−α)    ⇒ a=6  b=4.62  c=3.38        α=95.93°  β=50°  γ=34.07°    2. b=6  β=50° b+c=8 ⇒ c=2  α+γ=130° ⇒ γ=130°−α  a^2 =36+4−24cos α  36=a^2 +4−4acos 50°  4=a^2 +36−12acos (130°−α)    ⇒ a=7.09  b=6  c=2        α=115.21°  β=50°  γ=14.79°    3. c=6 β=50°  b+c=8 ⇒ b=2  α+γ=130° ⇒ γ=130°−α  a^2 =4+36−24cos α  4=a^2 +36−12acos 50°  36=a^2 +4−4acos (130°−α)    ⇒ no real solution

BC=aCA=bAB=c1.a=6β=50°b+c=8c=8bα+γ=130°γ=130°α36=b2+(8b)22b(8b)cosαb2=36+(8b)212(8b)cos50°(8b)2=36+b212bcos(130°α)a=6b=4.62c=3.38α=95.93°β=50°γ=34.07°2.b=6β=50°b+c=8c=2α+γ=130°γ=130°αa2=36+424cosα36=a2+44acos50°4=a2+3612acos(130°α)a=7.09b=6c=2α=115.21°β=50°γ=14.79°3.c=6β=50°b+c=8b=2α+γ=130°γ=130°αa2=4+3624cosα4=a2+3612acos50°36=a2+44acos(130°α)norealsolution

Answered by MrW3 last updated on 05/Sep/18

Commented by MrW3 last updated on 05/Sep/18

This is how to draw the searched triangle.  1. draw line BC=6  2. draw line BD=8 with ∠B=50°  3. connect D with C  4. draw perpendicular bisector of DC which  intersects with BD at A  5. connect A with C  ΔABC is the searched triangle.  proof:  AC=AD  AB+AC=AB+AD=BD=8

Thisishowtodrawthesearchedtriangle.1.drawlineBC=62.drawlineBD=8withB=50°3.connectDwithC4.drawperpendicularbisectorofDCwhichintersectswithBDatA5.connectAwithCΔABCisthesearchedtriangle.proof:AC=ADAB+AC=AB+AD=BD=8

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