Geometry
posted by Lizii .
In equilateral triangle ABC, AB=3x and BC=2x+12. Find the numerical value of the perimeter of triangle ABC.

Since it's an equilateral triangle, AB=BC. 3x=2x+12, solve for x.

In an Equilateral triangle, all 3 sides are equal.
Therefore AB = BC = CA
So, 3x = 2x + 12
Subtract 2x from both sides of the equation
3x  2x = 2x + 12  2x
x = 12
Therefore AB = 3x = 3 x 12 = 36
Perimeter = AB + BC + CA = 3AB = 3 x 36 = 108
Respond to this Question
Similar Questions

math
In equilateral triangle ABC, AB=3x and BC= 2x=12. Find the numerical value of the perimeter of ABC. 
geometry
Triangle ABC is a right triangle such that m angle B= 90 degrees. If AC= 12 and BC=9, what is the perimeter of triangle ABC ? 
geometry
in the diagram below of triangle abc, de is a midsegment of triangle abc, de=7, ab=10, and bc=13.find the perimeter 
geometry
Triangle ABC is an equilateral triangle with sides of 1. Arcs are drawn from A,B,C. what is the perimeter? 
Centroids and Triangles  determining perimeter?
Let G denote the centroid of triangle ABC. If triangle ABG is equilateral with side length 2, then determine the perimeter of triangle ABC. I drew the diagram, but it doesn't really help.... 
geometry
Open that link please please help me with my assignments 1. in the figure , the areas of traingle cef, triangle abe, triangle adf are 3,4, and 5 respectively. find the area of triangle aef 2. equialateral triangle abc has an area of … 
Hard Geometry Problem
Hi guys. I need a lot of help on this. "Equilateral triangle ABC has centroid G. Triangle A'B'C' is the image of triangle ABC upon a dilation with center G and scale factor 2/3. Let K be the area of the region that is within both … 
Geometry
Let ABC be any triangle. Equilateral triangles BCX, ACY, and BAZ are constructed such that none of these triangles overlaps triangle ABC. a) Draw a triangle ABC and then sketch the remainder of the figure. It will help if (triangle) … 
geometry
The altitude of equilateral triangle ABC is 15. What is the length of a side of triangle ABC? 
Geometry
In triangle ABC, AD bisects angle A, BD=4 and CD=5. The perimeter of triangle ABC is 29. Find the lengths of AB and AC.