Using Proportion and Cross Multiplication

[luisclementeortegasegovia]

Proportionality is a great tool and many teachers don't teach it as it should. 👍

[rook]

Holy, you just taught me what the US education system has failed to. Thank you

[taebong]

This is not how they teach us, so i didn't get it before. Thank you

[AtLeastThreeCharacters.]

I did it as a trigonometry problem;

tan(arctan(6/10)=B/800

[FlashRetired]

Please make a video on ratio and proportion, i mean when we have to put two things in proportion to get solution?
Thanks in advance and good content as always 🙏

[AYA-GAMING_SHORTS]

I SOLVED IT EASILY.🤘😎🤘

THANKS FOR THE QUESTION.👍🏻👍🏻

[yumechuu]

Another way would be to simply expand the first fraction by a factor which is equal to the proportion of 10 to 800, which (after crossing out a zero from both) can easily be seen to be 80. So 6/10 expanded by 80 = 480/800

[Lalalalalalalall]

I'm sorry but I just wanted to ask in which country is it an 8th grade question? Like I wanna know coz in India this seems like a 5-6th grade question. Just curious.

[dan-the-mansogynist]

How do you calculate this for trees in the building?

[eugenepluta]

I learned this in 6th grade and it's preciely this that sparked my fasination with math into audulthood.

[darkmxth]

While this works great for these types of problems, it falls short when applied to real life. Since we don't know how close the tree is to the building or how far apart the measurements are taken, the position of the sun could've changed and thus affect the length of the shadow. This in turn will give us an incorrect answer using the proportion

[maxeskie]

🤯 Mr H, this is so helpful! I need a lot of help in math. Do you offer private tutoring?

[Coolpidgeon]

I just simplified 6/10 as 3/5 and then went on to find 3/5 of 800 to get 480

[Mursal-mohamed]

Why we use dividing method . Why the relation between the tall of tree and his shadow is dividing?

[shubham-eknr]

Sir i used basic proportionality theorem of similar triangle

[Brid]

Exactly how I did it, but the numerator and denominator was switched on both sides
Basically what I thought is that, there are 2 shadow measurements and 1 real measurement so let us say that the real measurements are R1 and R2 and the shadow measurements are S1 and S2
So I can say that,
S1/R1=S2/R2
So, 10/6=800/R2
So by cross multiplying I get that:
10*R2=800*6
R2=80*6=480
Therefore the height of the building is 480 feet

[RakeshPrabhakara]

Let me add some conditions: 6 ft tree's shadow was 10 ft long at 4 pm. What would the building height be if it's shadow is 800 feet long at 4.05pm (assuming that you took 5 mins to solve the above problem)

[alexungureanu]

I have learned this in 6th grade and we call it the 3simple rule.

[Taro-mdzt]

What happens when the tree is so tall that it is taller than the light? 😂😂😂

[anonymousownerr]

Asians be like these are my favourite questions easy peasy 😂