(Lecture - 01)
Pythagorean Theorem
by Apurba Ghosh
Assistant Professor
Department of MCT
Daffodil International University
What is Pythagorean Theorem?
• Pythagoras was a Greek mathematician and philosopher. He lived in Samos during the
6th century B.C. He proved a very important rule of mathematics related to right-angled
triangles. A theorem is a rule in math that has logical proof. Since Pythagoras successfully
proved the theorem related to right-angled triangles, it is called the Pythagorean
theorem.
• The Pythagorean theorem is among the most important topics of mathematics, and it
describes the relationship between the sides of a right-angled triangle.
• The core aspect of this theorem is to find the measure of an unknown length or an
unknown angle of a right-angled triangle. We can derive formulas on the base, height and
hypotenuse of a triangle with the help of this theorem. Let’s understand this theorem in
detail.
Pythagorean Theorem Statement
• The Pythagorean theorem states that “In any right-angled triangle,
the sum of the squares of the lengths of the legs is equal to the
square of the length of the hypotenuse”. The legs of this triangle are
the shorter sides and the longest side, opposite the 90-degree angle,
is called the hypotenuse.
• Sides a and b form the legs and side c forms the hypotenuse of the
right triangle.
Pythagorean Theorem Formula - 1
Pythagorean Theorem Formula - 2
Draw a right-angled triangle with one side
along the horizontal and the second side
along the vertical on a grid paper.
Mark the measure of the two shorter
sides as a and b and the measure of the
longest side as c.
Pythagorean Theorem Formula - 3
Applications of Pythagorean Theorem
We can use the Pythagorean theorem to:
• To determine whether a triangle is right-angled or not.
• To find the length of unknown sides in a right-angled triangle and
three-dimensional figures.
• To find the distance between two points on a coordinate plane.
Pythagorean Theorem
Examples
Correct Answer: 65
Correct Answer: 90
Correct Answer: 12.6
Correct Answer: 10
Thank You All