Height (h) of cone = 15 cm
Let the radius of the cone be r.
Volume of cone = 1570 cm3
\(\frac{1}{3}\pi\)r²h = 1570 cm³
r² =\(\frac{\text{ (1570 cm³ × 3) }}{ \pi h}\)
r² = \(\frac{\text{(1570 cm³ × 3) }}{\text{ (3.14 × 15 cm) }}\)= 100 cm²
r = \(\sqrt{100}\) cm²
r = 10 cm
Therefore, the radius of the base of cone is 10 cm.
Factorise each of the following:
(i) 8a 3 + b 3 + 12a 2b + 6ab2
(ii) 8a 3 – b 3 – 12a 2b + 6ab2
(iii) 27 – 125a 3 – 135a + 225a 2
(iv) 64a 3 – 27b 3 – 144a 2b + 108ab2
(v) 27p 3 – \(\frac{1}{ 216}\) – \(\frac{9 }{ 2}\) p2 + \(\frac{1 }{4}\) p
Find the value of the polynomial 5x – 4x 2 + 3 at
(i) x = 0 (ii) x = –1 (iii) x = 2