Question

Find the cube root of -2.744 [4 MARKS]

Answer 1

Concept: 1 Mark
Application: 2 Marks

$-2.744=\frac{-2744}{1000}$

By estimation 2744 = 2(group 1) 744(group 2)

The second group has 4 as its unit digit. Therefore, its root will also have 4 at its unit digit.

Now 2 lies between 1 and 8 which is the cube of 1 and 2 respectively.

1 being the smaller of these, the tens place of the cube root will be 1.

So the cube root will be 14

Cube root of 1000 = 10

$(\frac{-2744}{1000}{)}^{\frac{1}{3}}=\frac{-14}{10}=-1.4$