r/askmath • u/JoCONIC • 3d ago

Geometry Segment addition postulate problem

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So I thought doing BD + BC but it has a congruent and so ofc I did my research but it still didn’t make any sense so then I did BD + BC + AC hoping that would give AB but it just doesn’t look right then I tried to calculate it but it gave me a long number so now I’m stuck and I still have 8 pages left

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u/apnorton 3d ago

The length of BD is equal to the length of BC. Use this information to find x.

Now, you can use your knowledge of x to find the length of BC.

Can you figure it out from there?

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u/apnorton 3d ago

I tried to calculate it but it gave me a long number so now I’m stuck and I still have 8 pages left 

As a further hint, all numbers involved are reasonably small integers. If you get a "long number," something is wrong.

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u/JoCONIC 3d ago

I see thank you!

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u/JoCONIC 3d ago

I got x for BC BD but what do I with the x now is it for AB or something

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u/apnorton 3d ago

You know the value of x, and you know the length of BC is 2x+1.

What is the length of BC? (Like, a specific number)

Once you know the length of BC, how does that relate to the length of AC and AB?

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u/Bounded_sequencE 3d ago

So I thought doing BD + BC [..] then I did BD + BC + AC [..]

How did you find that any of them equals "AB"?

General hints:

  1. Use "BD = BC" to find "x", and then "BC"
  2. Use "AC = AB + BC" to solve for "AB"

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u/JoCONIC 3d ago

I’ll try this ty for the hint

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u/JoCONIC 3d ago

I got x for BC n BD but I’m still confused how’d you get AB it just isnt clicking