ACT Preparation / Unit 14 ACT 1306 short lesson, about 20 seconds
Tangent and Radius
Captions available
The idea
A tangent touches a circle at one point and is perpendicular to the radius drawn to that point.
In practice
From a point 13 units from the center of a circle of radius 5, the tangent has length 12, from a right triangle.
Where people slip
The right angle sits at the point of tangency, which makes the Pythagorean theorem available.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Unlocks
- Nothing yet depends on this.
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