Math Is Fun Forum

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Equilateral Triangle

Problem 56; page 8.
Precalculus.

An equilateral triangle is one in which all three sides are of equal length. If two vertices of an equilateral triangle are (0, 4) and (0, 0), find the third vertex. How many of these triangles are possible?

For this one I do need the first-two steps.

1. How do I find the third vertex?

2. How many of these triangles are possible?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,626

Re: Equilateral Triangle

This is made easier because the given points lie on the y axis.

Find the midpoint.  A line perpendicular to this will go through the third vertex. So you can say what it's y coordinate is.  Call it's x coordinate 'x' and use the distance formula (distance will be = 4) to find x.  Two solutions.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mathxyz

Member

From: Brooklyn, NY

Registered: 2024-02-24

Posts: 1,053

Re: Equilateral Triangle

This is made easier because the given points lie on the y axis.

Find the midpoint.  A line perpendicular to this will go through the third vertex. So you can say what it's y coordinate is.  Call it's x coordinate 'x' and use the distance formula (distance will be = 4) to find x.  Two solutions.

Bob

Sounds good. I will also do this on paper and only return here if I get stuck.