Memorize these 2 triangles — half the SAT geometry section #shorts #SATMath #ACTMath

Added: 2026-05-17

[00:00:00]Memorize these two triangles. They show up on half the SAT geometry section.

[00:00:05]A 30-60-90 triangle has a hypotenuse of 10.

[00:00:09]What's the shortest side? A is 5, B is 5 root 2, C is 5 root 3, D is 10.

[00:00:16]The trig way. Use sine of 30 equals opposite over hypotenuse. Short side equals 10 * sine of 30. Calculator, brain cycles.

[00:00:26]There's a faster way.

[00:00:28]The hack. Just memorize two ratios.

[00:00:31]30-60-90, 1 to root 3 to 2.

[00:00:35]45-45-90, 1 to 1 to root 2.

[00:00:39]Hypotenuse is 10, divide by 2.

[00:00:42]Short side is 5.

[00:00:44]Answer, A, 2 seconds.

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