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In triangle △ABC, ∠ABC=90°, BH is an altitude. Find the missing lengths. AB=4 and BC=3, Find AH, CH and BH.

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Answer:

  • AH = 3.2
  • CH = 1.8
  • BH = 2.4

Step-by-step explanation:

It can be convenient to compute the length of the hypotenuse of this triangle (AC). The Pythagorean theorem tells you ...

AC^2 = AB^2 + CB^2

AC^2 = 4^2 + 3^2 = 16 + 9 = 25

AC = √25 = 5

The altitude divides ∆ABC into similar triangles ∆AHB and ∆BHC. The scale factor for ∆AHB is ...

scale factor ∆ABC to ∆AHB = AB/AC = 4/5 = 0.8

And the scale factor to ∆BHC is ...

scale factor ∆ABC to ∆BHC = BC/AC = 3/5 = 0.6

Then the side AH is 0.8·AB = 0.8·4 = 3.2

And the side CH is 0.6·BC = 0.6·3 = 1.8

These two side lengths should add to the length AC = 5, and they do.

The remaining side BH can be found from either scale factor:

BH = AB·0.6 = BC·0.8 = 4·0.6 = 3·0.8 = 2.4

_____

The sides of interest are ...

AH = 3.2

CH = 1.8

BH = 2.4

In triangle △ABC, ∠ABC=90°, BH is an altitude. Find the missing lengths. AB=4 and-example-1
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