Curved Surface Area of Cone || for Class 9 in Hindi 

At 5:43 R and l toh same h butt wo appas m cancel out kyun nhi hua?

@@BabitaKumari-ui7ez r cone ke base circle ka radius h aur l sector ke circle ka radius..dono alg h alg circle ke radius hai

Cube, cuboid, cylinder..ye to esy h. i)ᴄᴜʙᴇ..square se bnta h, cube me 6faces hote h yani 6sqrs 1sqr ka area agr a² to 6faces ka 6a².. => TSA=6a² Same, LSA=4a²..bcs 4faces hogye Yani 4sqrs ii)ᴄᴜʙᴏɪᴅ.. Ye 6rectangles se bnta h.. Top & bottom dono same dimensions ke h l & b.. To area(top & bottom)=lb+lb=2lb Ab 4walls.. To ek side ke opp walls ka hoga bh+bh=2bh And othr side ke opp walls ka lh+lh=2lh.. So, tsa=2(lb+bh+hl) iii)ᴄyʟɪɴᴅᴇʀ.. Ye circle se bnta h.. Circle ke upr circle rkh ke jse sikke ke upr sikka.. CSA=2πrh.. 1circle ka crcmfrnc=2πr..ab yhi circumfrnc pure h height tk ja rha h, that's y..2πr×h=2πrh Baki total ke liye top & base ke circles ke area ko add kr do.. To TSA=2πrh+2πr²

Cuboid cube are so easy you can derive it yourself Cylinder is also kinda ez

@@BabitaKumari-ui7ez R is the radius of Sector (when it forms radius of circle in the base of cone) . And L is the radius of circle. L and R are not same

At 5:43 R and l toh same h butt wo appas m cancel out kyun nhi hua?

@@BabitaKumari-ui7ez R aur L different hai. R cone ke base ka radius hai aur l cone ka slant height hai. Btw wo same hote to bhi cancel nahi hote r² ya phir l² hota

At 5:43 R and l toh same h butt wo appas m cancel out kyun nhi hua?

@@BabitaKumari-ui7ez 'r' and 'l' are not same. 'r' is the radius of the Base of the Cone and 'l' is the slant height of the Cone. Therefore l² = r² + h²

Nice

Thank you very much for your huge support. 🙏🙏🙏

At 5:43 R and l toh same h butt wo appas m cancel out kyun nhi hua?

Power point

Sir please aap hummari cube ,cuboid kai b video lecture aaisahii deknayia........... Because aaisa aachay sai clear hota hai plzzzzzzzzzzzzzzzz sir

been*

@@nxvagamer7726 edit option exists

Almost every topic is vailable.

Kyonki circle ka circumference÷daimeter'= 3.14... (1) jise ki hum π kahte hai. Aur jaisa ki hme pata hai ki daimeter radius ka duguna hota hai yane, Daimeter= 2r. To equation number (1) me Daimeter ki value 2r rakhne par: •Circumference ÷2r=π then Circumference= 2πr. I hope😃 you got the answer.

At 5:43 R and l toh same h butt wo appas m cancel out kyun nhi hua?