The Academy ratio of 1.375:1 (abbreviated as 1.37:1) is an aspect ratio of a frame of 35 mm film when used with 4-perf pulldown. It was standardized by the Academy of Motion Picture Arts and Sciences as the standard film aspect ratio in 1932, although similar-sized ratios were used as early as 1928. (Wikipedia).

Equivalent ratios

From playlist Algebra 1 | Get Ready for Grade Level | Khan Academy

This video defines a ratio and provides several examples on how to write a ratio and shows how to simplify a ratio. http://mathispower4u.wordpress.com/

From playlist Ratios and Rates

Without evaluating, write several equivalent expressions to represent 2% of 90.

From playlist Ratios, rates, and percentages | 6th Grade | Khan Academy

This video introduces the Golden ratio and provides several examples of where the Golden ratio appears. http:mathispower4u.com

From playlist Mathematics General Interest

Ratios Introduction - what are ratios?

Ratios are used to compare different quantities. In this introduction to ratios we will look at what ratios are, how we deal with ratios of different measurement units and that ratios can be simplified. To donate to the tecmath channel:https://paypal.me/tecmath To support tecmath on Pa

From playlist Ratios

This is a short video tutorial on equivalent ratios. ✤ ✤ ✤ INTERACTIVE APPLETS AND WORKSHEETS ✤ ✤ ✤ http://fearlessmath.net ✤ ✤ ✤ FOLLOW ME ON TWITTER ✤ ✤ ✤ http://twitter.com/dhabecker

From playlist All about ratios and proportions

Is the beauty of Charlize Theron based on a myth? Does her face really have the golden ratio? Are the aesthetics that we are drawn into far from individual aesthetic understanding? Does the golden ratio compel us to like certain types of beauty? Or have we been led to believe a lie? Let

From playlist Myth or Fact?

Using similarity to estimate ratio between side lengths | High school geometry | Khan Academy

When two right triangles share an acute angle measure, the ratios of the corresponding side lengths within the triangles are equal. View more lessons or practice this subject at https://www.khanacademy.org/math/geometry/hs-geo-trig/hs-geo-ratios-in-right-triangles . Khan Academy is a non

From playlist Algebra 2 | Get Ready for Grade Level | Khan Academy

Modeling ticket fines with exponential function | Algebra II | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/algebra/x2f8bb11595b61c86:exponential-growth-decay/x2f8bb11595b61c86:exponential-functions-from-tables-graphs/v/modeling-ticket-fines-with-exponential-function Pra

From playlist Mathematics I | High School Math | Khan Academy

Ratio test | Series | AP Calculus BC | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/ap-calculus-bc/bc-series-new/bc-10-8/v/ratio-test-convergence The ratio test is a most useful test for series convergence. It caries over intuition from geometric

From playlist Series | AP Calculus BC | Khan Academy

Ratio problem with basic algebra | Linear equations and inequalities | Algebra Basics | Khan Academy

A slightly more involved ratio problem with algebra. Created by Sal Khan. Practice this yourself on Khan Academy right now: https://www.khanacademy.org/math/algebra-basics/core-algebra-linear-equations-inequalities/ratios-core-algebra/e/constructing-proportions-to-solve-application-proble

From playlist Linear equations and inequalities | Algebra Basics | Khan Academy

The golden ratio | Introduction to Euclidean geometry | Geometry | Khan Academy

Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now: https://www.khanacademy.org/math/geometry-home/geometry-lines/the-golden-ratio/v/the-golden-ratio An introduction to one of the most amazing ideas/numbers in mathematics Watch the next lesson: h

From playlist Introduction to Euclidean geometry | Geometry | Khan Academy

Operant conditioning: Schedules of reinforcement | Behavior | MCAT | Khan Academy

Created by Jeffrey Walsh. Watch the next lesson: https://www.khanacademy.org/test-prep/mcat/behavior/learning-slug/v/operant-conditioning-innate-vs-learned-behaviors?utm_source=YT&utm_medium=Desc&utm_campaign=mcat Missed the previous lesson? https://www.khanacademy.org/test-prep/mcat/beh

From playlist Behavior | MCAT | Khan Academy

Introduction to ratios | Ratios, rates, and percentages | 6th grade | Khan Academy

Learn how to find the ratio between two things. In this video, we find the ratio of apples to oranges. Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-ratios-prop-topic/cc-6th-ratios-intro/e/representing-ratios?utm_s

From playlist Algebra 1 | Get Ready for Grade Level | Khan Academy

Ratios as fractions | Ratios, rates, and percentages | 6th grade | Khan Academy

How are fractions and ratios the same? How are they different? Is 2:5 the same as 2/5? Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-ratios-prop-topic/cc-6th-ratios-intro/e/representing-ratios?utm_source=YT&utm_med

From playlist Algebra 1 | Get Ready for Grade Level | Khan Academy

2015 AP Calculus BC 6a | AP Calculus BC solved exams | AP Calculus BC | Khan Academy

Ratio test. Watch the next lesson: https://www.khanacademy.org/math/ap-calculus-bc/bc-solved-exams/bc-solved-exams-2015/v/2015-ap-calculus-bc-6b?utm_source=YT&utm_medium=Desc&utm_campaign=APCalculusBC Missed the previous lesson? https://www.khanacademy.org/math/ap-calculus-bc/bc-solved-e

From playlist AP Calculus BC solved exams | AP Calculus BC | Khan Academy

Angle bisector theorem proof | Special properties and parts of triangles | Geometry | Khan Academy

What the angle bisector theorem is and its proof Watch the next lesson: https://www.khanacademy.org/math/geometry/triangle-properties/angle_bisectors/v/angle-bisector-theorem-examples?utm_source=YT&utm_medium=Desc&utm_campaign=Geometry Missed the previous lesson? https://www.khanacademy

From playlist High School Geometry | High School Math | Khan Academy

Golden ratio and Rembrandt's self portrait | Similarity | Geometry | Khan Academy

Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/geometry/similarity/cc-solving-prob-similar-tri/e/solving-problems-with-similar-and-congruent-triangles?utm_source=YT&utm_medium=Desc&utm_campaign=Geometry Watch the next lesson: https://www.khan

From playlist High School Geometry | High School Math | Khan Academy

Defining and Finding the Value of the Golden Ratio

This video focuses explores the great number Phi, also known as the Golden Ratio. The definition and exact value of the Golden Ratio is explained in this video. This Golden Ratio video series seeks to explore one of the most significant numbers in mathematics. This goal of this video se

From playlist Golden Ratio Series