Uploaded July 2026 | Updated September 2026, 2 weeks ago
In this video, we explore different methods for finding the area of triangles through clear visualizations and step‑by‑step explanations. Starting with an introduction, we derive the formula for the area of an equilateral triangle, followed by the formula for an isosceles triangle. The lesson then covers the area of a right‑angled triangle, highlighting how its unique properties simplify calculations. Finally, we look at how to determine the area of a triangle when the radius of the circumcircle or incircle is known, connecting circle geometry with triangle properties.
Courses on Khan Academy are always 100% free. Start practicing and saving your progress now!
khanacademy.org/math/ncert-math-class-9-new/x56891bfac37feca0:measuring-space-perimeter-and-area
Timestamps:
00:00 Introduction
00:37 Finding the formula for area of equilateral triangle
02:59 Finding the formula for area of isosceles triangle
05:04 Finding the formula for area of right angled triangle
05:57 Area of triangle when radius of circumcircle and incircle is known
Khan Academy India is a nonprofit organization with the mission of providing a free world-class education for anyone anywhere. We have videos and exercises that have been translated into multiple Indian languages and 15 million people around the globe learn on Khan Academy every month.
Support Us: india.khanacademy.org/donate
In this video, we explore different methods for finding the area of triangles through clear visualizations and step‑by‑step explanations. Starting with an introduction, we derive the formula for the area of an equilateral triangle, followed by the formula for an isosceles triangle. The lesson then covers the area of a right‑angled triangle, highlighting how its unique properties simplify calculations. Finally, we look at how to determine the area of a triangle when the radius of the circumcircle or incircle is known, connecting circle geometry with triangle properties.
Courses on Khan Academy are always 100% free. Start practicing and saving your progress now!
khanacademy.org/math/ncert-math-class-9-new/x56891bfac37feca0:measuring-space-perimeter-and-area
Timestamps:
00:00 Introduction
00:37 Finding the formula for area of equilateral triangle
02:59 Finding the formula for area of isosceles triangle
05:04 Finding the formula for area of right angled triangle
05:57 Area of triangle when radius of circumcircle and incircle is known
Khan Academy India is a nonprofit organization with the mission of providing a free world-class education for anyone anywhere. We have videos and exercises that have been translated into multiple Indian languages and 15 million people around the globe learn on Khan Academy every month.
Support Us: india.khanacademy.org/donate
