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PSAT Math Diagnostic Videos 41 videos
PSAT 1.10 Math Diagnostic. Which of the following is a factor of the expression?
PSAT 1.3 Math Diagnostic. Which of the following most nearly represents the line of best fit?
PSAT 1.4 Math Diagnostic. Which of the following conclusions is supported by the data in the graph?
PSAT 1.25 Math Diagnostic 190 Views
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Description:
PSAT 1.25 Math Diagnostic. What is the area of the shaded sector in square cm?
More Video DetailsTranscript
- 00:00
Thank you We sneak and here's your smoke du jour
- 00:05
brought to you by minor arcs like the one built
- 00:08
by know his next door neighbor and joyce and only
- 00:10
fit about a dozen animals and well they were all
- 00:12
cats You're welcome new world Oh and check out this
Full Transcript
- 00:15
diagram of a nup side down and twisted icecream cone
- 00:18
circle Why shown in the diagram above has a diameter
- 00:21
of ten centimetres If m equals forty five degrees and
- 00:24
the length of the minor arc x z is ten
- 00:27
thirds pi centimeters What is the area of the shaded
- 00:31
sector in square centimeters and hear the potential answers a
- 00:35
lot of friends So we have a nagging feeling We're
- 00:38
going to have to use our brains on this one
- 00:39
Hope we remember to bring the charger right Let's recap
- 00:41
what we know Looking at the diagram we're told that
- 00:44
the diameter of this circle is ten centimeters which makes
- 00:46
the radius this thing right here Half that or five
- 00:49
centimeters were also told that the measure of the angle
- 00:52
is forty five degrees Him right there And the minor
- 00:55
arc length of x is ten thirds pi centimeters We're
- 00:58
looking for the area of this grayish section over here
- 01:02
So what do we do next Is it time to
- 01:03
use a lifeline waken do this because circles are our
- 01:07
jam We already know that circumference equals diameter times pi
- 01:11
making the circumference of this circle ten pie since the
- 01:15
arc x z is ten thirds pi or one third
- 01:18
of the total length the angle x y z must
- 01:21
be a third of the total angle measurement as well
- 01:23
which is always three hundred sixty degrees when dealing with
- 01:25
the circle one third of three sixty is one twenty
- 01:29
What this also means is that the area of the
- 01:31
unshaded part of the circle is gonna be exactly one
- 01:34
third of the area of the total circle While we
- 01:36
need to do now is find out the area of
- 01:38
the whole circle and then take two thirds of it
- 01:40
to find the area of the shaded portion Unfortunately we've
- 01:43
had the formula for the area of a circle grafted
- 01:45
onto the inside of our islands But we know it's
- 01:48
gonna be pi times are square where are is the
- 01:51
radius The area will be pi times five squared and
- 01:55
five squared is twenty five So the area's twenty five
- 01:58
pie piece of cake Finally you have to take two
- 02:01
thirds of the total area to get shaded portion twenty
- 02:03
five five times two thirds is fifty over three times
- 02:06
pi which is answer c thank very much Xy may
- 02:09
just be a minor arc but we have a feeling
- 02:11
it's gonna make it in the big leagues one day 00:02:13.823 --> [endTime] Maybe it will get to play for the rays
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