Soooooo, Do ya still like maths?

​@@mashrafusi like maths

@@chandrakalachan6592 good 😊 proud of u

Don't let a Maths teacher dictate your future remember that

@@apsingh1792 thanks man, this year I actually have a pretty good teacher and either way, math is fun to me now

*In radians

Facts

Not me. This was something I simply googled. Maybe you were just sitting on your fat, useless body, waiting for school, but others have to start quicker.

​@@Sh4dowbanned no need to be so rude though, gosh...😮‍💨

​​​@@Sh4dowbannedthat's rude and arrogant. You need to change some elements of your behaviour. Wish you a good day and life :)

@@KoczulMoczul mike is just the typical male teen who tries to make himself look cool online by being toxic but in reality he is just not.

@@mathguy3451 you need to have it in the back of your mind that since you are not that person then there is a good chance you don't know what influenced that person to behave this way. Such a person also needs support. Cheers :)

Yeah, I wondered why he'd chosen 70°, as that gives an exact area of 112π/9. Not the friendliest answer.

Tamir don't make excuses. Admit you are an asshole

lightsaber

You're welcome!

3.141592653

the only good math joke ive ever heard. Well done!

Thanks!

Thank you!

You're welcome!

Yep that works too!

Don't know how this works

​@@je6845it's just class 11 mathematics

You're welcome 😊

Use calculus.

Well, if it is a total eclipse, the area is zero. Unless you meant "ellipse."

Think of the ellipse as a vertically squished circle; any area in the ellipse is less than the corresponding area in the circle by the factor you squished it by. Now it's just a matter of finding the corresponding sector in the circle which you can do with some trig.

Ask Kepler. He'll know.

That works too!

You can't express a mixed fraction and then just multiply by variable or symbolized constant thats just janky looking. It looks like your saying 12 + (4/9)pi. You would have to write it as "improper", or if you were in my class I would give you credit if you put the mixed fraction in parentheses.

U don’t need a calculator just leave it in terms of pi For example if we had an angle of 90/360 and a radius of 10 we would do pi x r^2 which is pi x 10^2 which is 100 pi, since the angle is 90 we times this with 90/360 which gives us 25 pi as the answer and since we don’t have a calculator we just leave it in terms of pi

Thanks a lot 😊

Thanks!

You can't.

@@nilsalmgren4492 Is it possible to measure the angle somehow in a real world situation?

@@afifkhaja You can always use a protractor to measure the angle. You cannot know the angle by simply knowing the radius.

You would have to know the arc length of the sector in order to estimate the angle. If the arc length is equal to (theta/360)*2pi*radius, then you can solve for theta and see that it‘s equal to (arclength*360)/(2pi*radius). In this case, if we had 8cm as the radius and 9.77384 cm as the arc length, then (9.77384*360)/(16pi) would yield approximately 69.9999727, or around 70 degrees. Your precision will be dependent on how the arc length is given.

That's right!

The sides of a sector are the radius of the circle, not diameter

if you complete the circle, you can clearly see that 8cm is the radius.

Distance from center of the circle to a point on the circle is the radius.

Hello can u pls explain how did this guy get 39 for the answer.. And also 8sq =64 rite so nothing became of that in this equation

@@draymondgreen7606yes, 8² is 64. 64π is around 201 but you need to multiply that to 70/360 which reduces it to 39.

The arc length of the sector is fairly easy to calculate if you remember how to find the circumference of a circle, which is the diameter multiplied by pi. In this case, we have the radius, 8cm, so we know that the diameter is twice the radius, or 16cm. The circumference would be 16pi. From there, the arc length of the sector is the circumference of the circle multiplied by the ratio of the sector‘s angle to a full circle. This is similar to finding the area of the sector, which is the area of the circle multiplied by the ratio of the sector‘s angle to the full circle. Thus, the arc length would be (70/360)*16pi, or approximately 9.77384 cm. This is basically saying „if one degree of this circle equates to a length of 16pi/360 around the circumference, what is this length 70 times?“ (16pi/360)*70).

@@isaacbruce6652 Thank you for your elaborate, clear though a bit lengthy response. Now, in real life one often encounter curves that are not circular, for example, motorways. In elementary geometry, the ellipse, the parabola, the hipérbola... how does one calculate the arc length of different sections in any of these curves, say the ellipse? Measuring straight lines you use a tape measure between two points, you're done! Say, garden landscaping: Most likely you plan for curves in your garden which are not a section of a circumference. How to determine their length and therefore the exact quantity of material you need for building them? I am suspecting one needs basic calculus for this.

Sorry what-

I think you mean an ellipse, not an eclipse. An ellipse is an elongated circle, an eclipse is an astronomical event. Anyway, to find the area of a sector of an ellipse, you need to do a polar coordinate integral. Just like a regular integral, except instead of slicing the function's graph like bread, we're slicing it like a pizza. Assign r to be the radial distance from the origin, and θ to be the CCW angle in radians, from the +x axis, as is convention. Any given infinitesimal pizza slice will have the area of 1/2*r^2*dθ, where dθ means infinitesimal change in θ. An ellipse with semimajor and semiminor axes of a and b respectively, in polar coordinates is given by: r = sqrt(a^2*cos(θ)^2 + b^2*sin(θ)^2) Thus r^2 = a^2*cos(θ)^2 + b^2*sin(θ)^2 Integrate relative to θ: cos(θ)^2 = 1/2*(1 + cos(2*θ)) sin(θ)^2 = 1/2*(1 - cos(2*θ)) integral cos(θ)^2 dθ = 1/2*θ + 1/4*sin(2*θ) integral sin(θ)^2 dθ = 1/2*θ - 1/4*sin(2*θ) integral 1/2*r^2 dθ = a^2*(θ/4 + 1/8 sin(2*θ)) + b^2*(θ/4 - 1/8*sin(2*θ)) + C Evaluate across the angles or interest. Suppose we want to make a 45 degree (i.e. pi/4 radian) elliptical sector, starting on the x-axis. Evaluate from 0 to pi/4: a^2*(pi/16 + 1/8 sin(2*pi/4)) + b^2*(pi/16 - 1/8*sin(2*pi/4)) Simplify, and we have our result: a^2*(pi/16 + 1/8) + b^2*(pi/16 - 1/8)

112π/9

Well, that would only work if the angle was 90°

Hello can u explain how this guy got the answer of 39. And isnt 8square =64

Bcuz 64×3.14×70/360=39.07(5)

@@trCore that guys an npc

Both are acceptable.

from all i can see, you must’ve either scaled 70 down by multiplying by 100 into 0.7, scaled up 360 by multiplying by 100 into 36000, or scaling down 8 by dividing by 10 into 0.8 any of these values substituted into the formula compute 0.39, and it is likely you may have accidentally inputted a decimal point into the calculator somewhere, for example: (.70/360)•(pi)•8^2 or (70/360)•(pi)•.8^2 both compute 0.39cm^2 to two d.p.

​@@joel6282ohh man.., you told all the possibilities of error to get .39 I salute you!!

You only need the radius and the angle to find the area of the sector, since it‘s a fraction of the area of the circle with the same radius.

'worng' 🤣🤣

Failed maths, did we?

The formula for the area of a circle is pi × the radius². Pi is about 3.14, and the radius is 8 centimeters. That means the area of a full circle with a radious of 8 centimeters would be about 200.96 centimeters. The area we are asked to find isn't a full circle though, it is 70/360 or 7/36 of the full circle. 7/36 × 200.96 is about 39.07 centimeters which is the answer.

I used to write x for an unknown variable in a much fancier way than the simple x I used to indicate multiplication. I know you can't tell the difference in this comment but you could in my handwriting.