finite-geometric-series-formula-justification-high-school-math-khan-academy

# Interactive video lesson plan for: Finite geometric series formula justification | High School Math | Khan Academy

#### Activity overview:

The finite geometric series formula is a(1-râ¿)/(1-r). In this video, Sal gives a pretty neat justification as to why the formula works.

Watch the next lesson: https://www.khanacademy.org/math/math-1-2-3/math3/math3-series/math3-geo-series-app/v/geometric-series-word-problem?utm_source=YT&utm_medium=Desc&utm_campaign=highschoolmath

Missed the previous lesson? https://www.khanacademy.org/math/math-1-2-3/math3/math3-series/math3-geo-series/v/three-examples-of-evaluating-finite-geometric-series?utm_source=YT&utm_medium=Desc&utm_campaign=highschoolmath

High School Math on Khan Academy: Did you realize that the word "algebra" comes from Arabic (just like "algorithm" and "al jazeera" and "Aladdin")? And what is so great about algebra anyway? This tutorial doesn't explore algebra so much as it introduces the history and ideas that underpin it.

About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world. Our resources cover preschool through early college education, including math, biology, chemistry, physics, economics, finance, history, grammar and more. We offer free personalized SAT test prep in partnership with the test developer, the College Board. Khan Academy has been translated into dozens of languages, and 100 million people use our platform worldwide every year. For more information, visit www.khanacademy.org, join us on Facebook or follow us on Twitter at @khanacademy. And remember, you can learn anything.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan Academyâs High School Math channel: https://www.youtube.com/channel/UCAj83VTec-NC-g0BK8zpxzw?guided_help_flow=3?sub_confirmation=1
Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy

Tagged under: education,online learning,learning,lessons

Clip makes it super easy to turn any public video into a formative assessment activity in your classroom.

Add multiple choice quizzes, questions and browse hundreds of approved, video lesson ideas for Clip

Make YouTube one of your teaching aids - Works perfectly with lesson micro-teaching plans

Play this activity

1. Students enter a simple code

2. You play the video

3. The students comment

4. You review and reflect

* Whiteboard required for teacher-paced activities

## Ready to see what elsecan do?

With four apps, each designed around existing classroom activities, Spiral gives you the power to do formative assessment with anything you teach.

Quickfire

Carry out a quickfire formative assessment to see what the whole class is thinking

Discuss

Create interactive presentations to spark creativity in class

Team Up

Student teams can create and share collaborative presentations from linked devices

Clip

Turn any public video into a live chat with questions and quizzes

### 1000s of teachers use Spiral to deliver awesome, engaging activities that capture students' understanding during lessons.

Now it's your turn Sign up

### Spiral Reviews by Teachers and Digital Learning Coaches

@kklaster

Tried out the canvas response option on @SpiralEducation & it's so awesome! Add text or drawings AND annotate an image! #R10tech

@3rdgradeBCE

Using @SpiralEducation in class for math review. Student approved! Thumbs up! Thanks.

@ordmiss

Absolutely amazing collaboration from year 10 today. 100% engagement and constant smiles from all #lovetsla #spiral

@strykerstennis

Students show better Interpersonal Writing skills than Speaking via @SpiralEducation Great #data #langchat folks!

@iladylayla

A good tool for supporting active #learning.

@BrettErenberg

The Team Up app is unlike anything I have ever seen. You left NOTHING out! So impressed!

## Get the Clip Chrome Extension & Create Video Lessons in Seconds

Add Clip to Chrome