ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Geometry and Measurement Videos 87 videos
SAT Math 1.1 Geometry and Measurement. What is the circumference of the circle?
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. Find the length of CE.
SAT Math: Calculating Arc Length Using Proportions 3 Views
Share It!
Description:
A circle has a radius of 6 and a central angle ∠XYZ that measures . What is the length of the major arc formed by the central angle?
Transcript
- 00:00
Yeah Whoa Okay Trig shmoop ear's A circle has a
- 00:06
radius of six and a central angle of X Y
- 00:09
Z That measures for pie over three radiance What's the
- 00:11
length of the major arc X Z formed by the
- 00:15
central angle All right so we gotta drive Little picture
Full Transcript
- 00:19
here It's gonna look like this I'm here to here's
- 00:22
to forty And then we got to X and line
- 00:24
Zeke And yes how rude it was of this problem
- 00:27
to not come with a drawing Yeah you have to
- 00:29
make one sometimes but that's because we're in America No
- 00:32
more participation trophies for you Start with the angle here
- 00:35
of four pi over three and converted to degrees We
- 00:39
had for pirating ins over three times the hundred degrees
- 00:42
over pi radiance That's how we got to two Forty
- 00:44
They're spinning counterclockwise Okay And this is how big the
- 00:48
central angle in the circle has to be This thing
- 00:51
which is a pretty big to forty big number Imagine
- 00:54
having to run around the circle to get from X
- 00:55
to Z by taking the longer route Well that's the
- 00:58
root of the major ark We need to measure and
- 01:00
to find the distance around a part of the circle
- 01:03
First find the distance around the full circle which is
- 01:05
the What's it called Oh yes Circumference Well the problem
- 01:08
says the radius is six and the circumference is always
- 01:11
two Pi r Right That's just by definition So sir
- 01:14
Come sir Go to buy our equals two high times
- 01:17
six which is twelve Pie Got it Simple That's the
- 01:20
circumference Well given the circumference here we can measure the
- 01:23
art by setting up a proportion We need to measure
- 01:25
the arc length created by two hundred forty degree arc
- 01:28
out of the full circle Three Sixty measure So what
- 01:31
is that Well we got to forty over three Sixty
- 01:33
There equals that arc x z over twelve pie because
- 01:37
that's a circumference right That's the three sixty Think so
- 01:40
reduces down to two thirds equals xy over twelve pie
- 01:43
Or send another way If we divide the numbers out
- 01:45
here we get well the ark XY is just a
- 01:48
pie So the length of the major arc X Z
- 01:51
formed by the central angle is a pirate's answer See
- 01:54
and remember this is a distance of the long way
- 01:57
From ecstasy not the short way which is for pie
- 02:00
They throw that curve ball like you There'd be and
- 02:02
twelve five's The total circumference on a portion of it
- 02:05
into pie is the full angle of a circle and
- 02:07
radiance so they're always going to give you answers here
- 02:10
That might seem logical on the way back part of 00:02:12.53 --> [endTime] your brain but aren't
Related Videos
SAT Math 2.1 Geometry and Measurement. What is the measure of angle z in terms of x and y?
In 2014, the unemployment rate of one county in California was 7%. In another county, the unemployment rate was 11%. Which of the following express...
Angela is making cookies for a bake sale. She expects each batch of her cookies to sell for $40. It costs her $10 to make one batch of cookies, and...