Question

Mark (✓) against the correct answer
$\sqrt{72}\times \sqrt{98}=?$
(a) 42
(b) 84
(c) 64
(d) 74

Answer 1

(b) 84

$\sqrt{72}\times \sqrt{98}=\sqrt{2\times 2\times 2\times 3\times 3}\times \sqrt{2\times 7\times 7}=\sqrt{2\times 2\times 2\times 3\times 3\times 2\times 7\times 7}=2\times 2\times 3\times 7=84$