Answer and Explanation:
Since this is a 30-60-90 triangle, you can use the ratio of side lengths specific to this type of triangle:
x = 4√(2)
y = 2(4) = 8
because where 4 = T,
x = T√2 and y = 2T
so again:
Two independent samples of size 50 and 50 to test the difference between the population means
1 answer:
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Answer: 64.8 mph
Step-by-step explanation:
Given
Arriving time is 6 hours
return time is 4 hours
The average speed of returning 81 mph
Distance traveled while returning
the average speed of the entire trip is
Answer: About 72 feet
The more accurate value is roughly 71.7260397 feet (however, this value isn't fully exact either).
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Explanation:
Check out the diagram below. It's effectively the same diagram your teacher provided, but I've added points M and N. I've left out any unnecessary lines.
- M = center of the circle
- N = location where the cable is anchored to the ground
We're told that "(the length of cable from) E to the ground is 35 feet", so this is the red portion of cable that I've marked this as NE = 35, ie segment NE is 35 feet long. We're also told that NF = 40 feet, which is also shown in red.
The blue portions are chords of the circle. We're given one chord as LE = 80 ft, while the other chord JF is what we want to find out.
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What we need to find is the radius of this circle. Right away, it's not clear what the radius is; however, we can use the chord LE = 80 to help find it.
It turns out that the chord length c is connected to the radius r and central angle theta like so:
c = 2*r*sin(0.5*theta)
where theta must be in radian mode. The central angle subtends the arc that forms the chord in question.
If we started at point L, and counted the number of spaces to get to E while going clockwise, then we can see that there are 5 spaces
Those five spaces could be written as
- The jump from L to A
- The jump from A to B
- The jump from B to C
- The jump from C to D
- The jump from D to E
Or you could mark it as such on the diagram for a visual reference. Overall, the circle has been cut into 12 equal slices. So going from L to E, going clockwise, will have us take up 5/12 of the full circle.
There are 2pi radians in a full circle, meaning the central angle LME is (5/12)*2pi = 5pi/6 radians.
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Plug theta = 5pi/6 and c = 80 into the formula mentioned. Isolate the radius.
c = 2*r*sin(0.5*theta)
80 = 2*r*sin(0.5*5pi/6)
80 = 2*r*sin(5pi/12)
80 = 2*r*0.9659258
80 = 2*0.9659258*r
80 = 1.9318516r
1.9318516r = 80
r = 80/1.931 8516
r = 41.4110483
The radius is approximate. The radius is in feet. Make sure your calculator is in radian mode.
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Now that we know the radius, we can determine how long chord JF is.
The central angle for chord JF is angle JMF
If we start at J and go to F, along the shorter path, then we've gone 4 spaces. This is 4/12 = 1/3 of the full circle. So the radian measure of angle JMF is (1/3)*2pi = 2pi/3 radians.
So,
c = 2*r*sin(0.5*theta)
c = 2*41.4110483*sin(0.5*2pi/3)
c = 71.7260397
Chord JF is roughly 71.7260397 feet long.
When rounding to the nearest foot, that's about 72 feet.
Answer:
Step-by-step explanation:
First, you gotta work out the hypotenuse of ABC, which is AC.
To do that, you need to figure out the scale factor between the two right-angled triangles. You can do that for this question because this is a similar shapes question.
12.5/5 = 2.5
The scale factor length between the two triangles is 2.5.
You can use 2.5 now to work out AC, so AC would be 13 x 2.5, which gives 32.5.
Now that you've got the hypotenuse and BC of ABC, you can use Pythagoras's theorem to work out the length of AB
Pythagoras's theorem =
a = BC = 12.5
b = AB = we need to work this out
c = AC (the hypotenuse we just worked out) = 32.5
Let's both simplify and rearrange this at the same time so that we have our b on one side.
= 1056.25 - 156.25
b =
b =
b = AB = 30 We've found b or AB, now we can work out the perimeter of ABC.
Perimeter of ABC = AB + BC + AC
= 30 + 12.5 + 32.5
= 75 Here's the perimeter for ABC.