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Geometry and Measurement Videos 87 videos

SAT Math 1.1 Geometry and Measurement
719 Views

SAT Math 1.1 Geometry and Measurement. What is the circumference of the circle?

SAT Math 1.2 Geometry and Measurement
246 Views

SAT Math: Geometry and Measurement Drill 1, Problem 2. If A = (0, 4), B = (-3, 2), and C = (1, 0), which point is in the interior of angle ABC?

SAT Math 1.3 Geometry and Measurement
231 Views

SAT Math 1.3 Geometry and Measurement. Find the length of CE.

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Calculating the Bisector Length of a Square 2 Views


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Description:

The figure above is a square with a side length of . What is the length of ?


Transcript

00:02

Okay Satay shmoop er's Another picture for you We got

00:05

a b c d here and one side's five times

00:08

grow to this looks like a square but we don't

00:10

see any of those right angle thing You so we

00:12

can assume it yet let's See what they say the

00:15

figure above the square Ok so what now We can

00:17

assume it with a side of length Five times where

00:20

to what's the length of a d All right Well

00:26

see the problem is special here You sure all problems

00:29

are unique Yes Your all problems are unique snowflakes whose

00:33

parents love them very much But cutting this square in

00:36

half makes two special right triangles So this problem is

00:39

well you know extra special So we just put in

00:41

the forty five degree lines there in a little box

00:44

thing He's there you had partial credit You'd lose Get

00:47

two points for all that Well the ninety degree corners

00:49

are perfectly divided in half by that by sector So

00:52

that splits the angle into two forty five degree angles

00:54

When the angles of a right triangle are forty five

00:56

forty five and ninety the triangle is called Yes a

00:59

special triangle So there we go We've got x and

01:02

then x and x times grow too well The two

01:05

legs are equal courtesy of the two equal angles and

01:08

the high pot news is a screw to two times

01:10

greater than legs Well one of the sides already has

01:13

a square to to there But if we multiply that

01:15

by the square root of to to get a d

01:17

well what happens This happens It looks like this five

01:20

times grow two times Two is five times two or

01:23

just ten So eighty is ten that's it And yes

01:27

we could've used the pythagorean theorem in the beginning and

01:29

just squared all sides and gotten you know square root

01:32

of this five times for two squared plus five from

01:34

room c squared You'll get fifty plus fifty a c

01:37

squared or one hundred and it's road one hundred ten

01:40

Yeah The diagram of the square can't equal the length

01:42

of the side so that sea would have been impossible

01:46

in the length of five times were over too well

01:48

that comes from cutting one of the sides in half

01:50

If you remember the this ratio this acts money maximum

01:54

Ratio for a forty five Forty five Ninety triangle but

01:56

to divide length by expert to instead of multiply well

01:59

then we'd get a diagonal of five as in be

02:02

so that ain't it either So just go with the 00:02:05.21 --> [endTime] war shmoop

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