Can YOU Find the Radius of This Circle?

Comments · 1.4K

• MA

  @MathQueenSusanne · 8 months ago · pinned

  Hello my lovelies! ❤️ If you’re enjoying this video, don’t forget to like and subscribe – it truly helps!<br>And if you’d love to support me even more, you can now join my channel: <a href="https://www.youtube.com/@mathqueensusanne/join">https://www.youtube.com/@mathqueensusanne/join</a> <br>Thank you for keeping this math journey going!

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• BI

  @bischandchips9421 · 8 months ago

  I just turned 65 after retiring from my engineering career. I was bored doing sudoku an came across this video. I was totally stumped. I realized that after I moved up to management positions, I rarely had to do mathematical problems by hand. Considering I aced advanced calculus in the 80s, it was humbling. I bet I can&apos;t run the 100 yard dash now either 😂. <br><br>So thanks for your channel. This was totally fun and I wish my teachers were as good as you are at explaining the logic.

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• YA

  @yarsmythe · 8 months ago

  No idea why this crossed my feed...but I watched the whole video and enjoyed it. I used to love mathematics in school.

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• RI

  @richardlanahan8089 · 8 months ago

  I am 73 so i forgot about tangent lengths. Aced algebra and geometry 60 years ago but &apos;unless you do it every day.&apos; Fun to follow

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• AN

  @anthonywilliams6764 · 8 months ago

  I haven&apos;t had so much fun for seventy years listening to your solution thank you.

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• VI

  @VinlandPath · 9 months ago

  I used to be a math teacher. Your content has helped me rediscover my love of math.

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• FI

  @finris1 · 8 months ago

  Another method you can use is extending the diagonal to make the shape a right triangle, with an inscribed circle. Then, using the base of the trapezoid, the extended height of the shape, and the extended diagonal, the radius of the circle is = (a + b - c)/2, where c would be the diagonal.<br> &nbsp; The diagonal, if extended would reach (7/2)r, so the sides of the right triangle would have smaller sides of 7 and (7/2)r, and a hypotenuse of length sqrt(196 + 49r^2)/2. All combined, r = (7 + (7/2)*r - sqrt(196 + 49r^2)/2)/2 = (7r + 14 - sqrt(196 + 49r^2)/4. Using algebra, solving for r results in 21/10 or 2.1.

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• BE

  @berniepragle948 · 8 months ago

  Not only are your Math skills excellent, but your voice is very clear and the timing and cadence of your speech makes you easy to follow. &nbsp;Thank you for your videos and have a very happy 2026!!

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• BE

  @bermudarailway · 8 months ago

  I wish I&apos;d had you as my maths teacher 55 years ago not only did I find that interesting, I actually enjoyed it.

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• ED

  @Ed-quadF · 9 months ago (edited)

  I love how you always ask, &quot;I&apos;m curious how you solved this problem&quot;. I just start laughing. (By watching you.)

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• RA

  @ralphstanley99 · 7 months ago

  I am a retired high school math/physics teacher. &nbsp;I enjoy these algebra problems involving geometric constructions. &nbsp;I can tell you most high school students are not proficient enough in basic geometry to apply the &quot;law of tangents&quot; which is crucial to construct the right triangle. &nbsp;Most students would ask, &quot;why can&apos;t I just measure the radius with a ruler?&quot; &nbsp;;-)

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• АР

  @АрсенОсманов-й3к · 8 months ago (edited)

  Такие задачи решаются в уме:<br>(2R - 3)/(7-2R) = 3/7<br>2R = 3+3x<br>2R=7-7x<br>14R=21+21x<br>6R=21-21x<br>20R=42<br>R=42/20 = 21/10 = 2.1

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