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secondary 4 | A Maths
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secondary 4 chevron_right A Maths

Please help

Date Posted: 2 years ago
Views: 125
Muhd Ilman Fahmi
Muhd Ilman Fahmi
2 years ago
the cylinder in the cone creates two similar cones, which also forms similar triangles. You can try to prove this.

Since the base of the bigger cone is 20, and height is 60 (ratio is 3), this means that the height of the smaller cone is 3 times its base also, hence 3r. From there you can solve for part (i).

You have the formula of the S.A. of cylinder (2*pi*r^2+ 2*pi*r*h). Substitute h as the expression in (i), and you get the answer for part (ii).

(iii) You should be able to do this question with differentiation. So is part (iv)

Hope it helps

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Kenneth Teng
Kenneth Teng's answer
7 answers (Tutor Details)
I hope I'm right haha