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1. In the diagram below, points A, B, C, and P are situated so that PA=2, PB=3, PC=4, and BC=5. What is the maximum possible area of triangle ABC?

Diagram: https://latex.artofproblemsolving.com/f/8/c/f8c4039f30c9ec08fd75e8d55b476ded54ceb800.png (background is transparent) 

 

2. In triangle ABC, \angle ABC = 90^\circ and AD is an angle bisector. If AB=90, BC=x, and AC=2x-6, then find the area of triangle ABC. Round your answer to the nearest integer. 

 

3. Medians \(\overline{DP}\) and \(\overline{EQ }\) of triangle DEF are perpendicular. If \(DP=18\) and \(EQ=24\), then what is \(DF\)

 Jan 25, 2019
edited by yasbib555  Jan 25, 2019
 #1
avatar+101103 
+1

3. Medians DP and EQ of triangle DEF are perpendicular....DP = 18  and  EQ =  24

 

Let the medians intersect at   M

 

Then   DM = (2/3)DP =  (2/3)18 =  12

And EM =  (1/3)EQ =  (1/3)(24) = 8

 

So.....using the Pythagorean Theorem, ......DQ  =   sqrt ( DM^2 + EM^2 )  =  sqrt (12^2 + 8^2)  =  sqrt (144 + 64) =

 

sqrt ( 208)  =  4sqrt (13)

 

But  DF = 2DQ =   2 * 4sqrt (13)  =   8sqrt (13)

 

 

cool cool cool

 Jan 25, 2019
 #2
avatar+283 
+1

thank you so much!!

yasbib555  Jan 26, 2019
 #3
avatar+101103 
+1

2. In triangle ABC, \angle ABC = 90° and AD is an angle bisector. If AB=90, BC=x, and AC=2x-6, then find the area of triangle ABC. Round your answer to the nearest integer. 

 

Don't see where the angle bisector comes into play, here.....

 

We have that

 

BC^2 + AB^2 = AC^2

 

x^2 + 90^2 =  (2x - 6)^2

 

x^2 + 90^2 =  4x^2 - 24x + 36

 

3x^2 - 24x  - 8064 = 0

 

x^2 - 8x - 2688 = 0    this factors as

 

(x - 56) (x + 48) = 0

 

x = 56

 

So....the area is   (1/2)product of leg lengths  = (1/2)(AB)(BC) = (1/2)(90)(56) = 2520 units^2

 

 

cool cool cool

 Jan 26, 2019

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