Respuesta :

Step-by-step explanation:

a) 24.7×52.3=1291.81

On rounding off to 3 significant digits we get

1290

b)

[tex] \sqrt{ {42}^{2} - {28}^{2} } [/tex]

[tex] \sqrt{1764 -784 } = \sqrt{980} [/tex]

=31.304951

On rounding off to 5 significant figures we get

=31.305

c)

[tex] \sqrt[3]{78} = 4.27265[/tex]

On rounding off to 2 significant figures we get

=4.3

Hence required answers

a)1290

b)31.305

c)4.3

I hope it helped you