A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 5 years ago

I have an equilateral triangle with a altitude dropped. The altitude is 15 and I am trying to find the sides. Can anyone help?

  • This Question is Closed
  1. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    You have to use Pythagoras' Theorem. The altitude can be dropped from the apex of the triangle from the base. If you do this, you'll see you end up with two congruent right-angled triangles. The sides of an equilateral triangle are all equal, so if you call the side length, a, then \[a^2=15^2+\left( \frac{a}{2} \right)^2 = 225+\frac{a^2}{4}\]That is\[a^2=225 + \frac{a^2}{4} \rightarrow 4a^2=900 +a^2 \rightarrow 3a^2=900 \]so\[a^2=\frac{900}{3}=300\]and therefore, \[a=\sqrt{300}=10\sqrt{3}\]

  2. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    The a/2 in the first step comes from the fact that the altitude dropped from the apex bisects the base.

  3. anonymous
    • 5 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Feel free do give me a fan point ;p

  4. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.