What is Apollonius Theorem?

Apollonius theorem is a theorem that relates the sides of triangle with its median. According to Apollonius theorem the addition of squares of two sides of triangle is equivalent to the square of half of third side plus square of the median that bisects the third side. By using this theorem, we can easily find the length of sides or median of the triangle.

Apollonius Theorem Statement

Apollonius theorem states that:

The sum of squares of two sides of the triangle is equal to the twice sum of squares of median bisecting third side and the half of the third side.

Apollonius Theorem Formula

The Apollonius theorem formula is given by:

AB2 + AC2 = 2[AD2 + (BC/2)2]

where,

  • AB, AC and BC are sides of triangle ABC
  • AD is the median bisecting side BC

Apollonius Theorem

Apollonius theorem is a theorem relating the length of median and the length of sides of a triangle. It states that the sum of the squares of any two sides of triangle equals to twice the square of half the third side and twice the square on the median bisecting the third side. In this article we will explore the Apollonius theorem, Apollonius theorem statement and Apollonius theorem formula. We will also discuss the Apollonius theorem proof and solve some examples related to it. Let’s start our learning on the topic “Apollonius Theorem.”

Table of Content

  • What is Apollonius Theorem?
    • Apollonius Theorem Statement
    • Apollonius Theorem Formula
  • Apollonius Theorem Proof
    • Proof by Pythagoras Theorem
    • Proof by Cosine Rule
    • Proof by Vectors
  • Relation of Apollonius Theorem with Other Theorems
  • Solved Examples on Apollonius Theorem
  • FAQs on Apollonius Theorem

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What is Apollonius Theorem?

Apollonius theorem is a theorem that relates the sides of triangle with its median. According to Apollonius theorem the addition of squares of two sides of triangle is equivalent to the square of half of third side plus square of the median that bisects the third side. By using this theorem, we can easily find the length of sides or median of the triangle....

Apollonius Theorem Proof

The three ways to prove Apollonius theorem are:...

Relation of Apollonius Theorem with Other Theorems

The Apollonius theorem is related to general form of Pythagoras theorem and a special case of Stewart’s theorem....

Solved Examples on Apollonius Theorem

Example 1: Find the length of the median in a triangle with sides 5 units, 10 units and 12 units. The median meets at side of 12 units....

Practice Questions on Apollonius Theorem

Q1. Find the length of the median in a triangle with sides 15 units, 9 units and 20 units. The median meets at side of 20 units....

FAQs on Apollonius Theorem

What is Apollonius’ Theorem Formula?...