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### Course: Geometry (all content)>Unit 4

Lesson 5: Angle bisectors

# Distance between a point & line

Thinking about the distance between a point and a line. Proof that a point on an angle bisector is equidistant to the sides of the angle and a point equidistant to the sides is on an angle bisector. Created by Sal Khan.

## Want to join the conversation?

• what does bisector even mean
• An angle bisector is a line that divides an angle into two equal angles.
• Do we ever actually learn about any of this in school? This has never come up....at all.
• It all depends on what grade you're in. Also I'll let you in on a secret. Even if you don't learn this in school, you'll be able to use this as a shortcut while your classmates will be struggling on concepts like this. It's all about having the upper hand.
• What is the "RSH" triangle proof that Sal mentions at 9: 11? What does the acronym stand for?
• RSH stands for Right angle with Side and Hypotenuse.
• What is meant by 'Arbitrary point'?
• The word 'Arbitrary' can be understood here as the word 'any'. So here Sal means 'any point'. There are many other definitions of the word Arbitrary, but those definitions can easily be found in online dictionaries, Wikipedia etc...
• Is RHS congruency criteria a part of RSH congruency criteria?
• I learned the HL theorem, Hypotenuse-Leg. It says that if the hypotenuse of two right triangles are congruent, and one leg of each are congruent, then the two right triangles are congruent. Is RHS the same?
(1 vote)
• Is Sal mispronouncing "equally distant" or is equidistant a word?
• Equidistant is a word, but it basically means "equally distant".
• if the line that splits the angle in haft does not make two equal angles then is it still called a bisector?
• I don't think so, because an angle bisector, by definition is is a segment that divides an angle into two equal angles.
(1 vote)
• On khan academy does it explain why SSA doesn't work
• ok, in my homework, it is set up like everything here, except we do not have to do anything with an extra letter like "e" .. so this extra step makes It not soo understandable.. My problem is this: <ABD is congruent to <DBC
m<ABD=<DBC
32 degrees+(x+7)degrees
x= ? (bisector is line segment BD)
(1 vote)
• I am not sure if I understood the question the way you expect.
Anyways,if those two angles are congruent it means their values are equal
i.e 32=x+7
32-7=x
x=25.