question_answer 23)

Express as km using decimals. (a) 8 m (b) 88 m (c) 8888 m (d) 70 km 5 m TIPS As we know that, \[\therefore \]\[2mm=2\times \frac{1}{10}cm=\frac{2}{10}cm=0.2cm\]\[10mm=1cm\Rightarrow 1mm=\frac{1}{10}cm\] So, to express m as, km multiply m by \[\therefore \] (i.e. thousandths).

Answer:

(a) We know that, \[30mm=30\times \frac{1}{10}cm=\frac{30}{10}cm=3cm\] \[10mm=1cm\Rightarrow 1mm=\frac{1}{10}cm\]\[\therefore \] (b) We know that, \[116mm=116\times \frac{1}{10}cm\] \[=\frac{116}{10}cn=11\frac{6}{10}cm=\left( 11+\frac{6}{10} \right)cm\] \[=(11+0.6)cm=11.6cm\] (c) We know that, \[10mm=1cm\Rightarrow 1mm=\frac{1}{10}cm\] \[\therefore \]\[4cm2mm=4cm+2mm\] (d) We know that, \[=4cm+2\times \frac{1}{10}cm=4cm+\frac{2}{10}cm\] \[=(4+0.2)cm=4.2cm\]\[10mm=1cm\Rightarrow 1mm=\frac{1}{10}cm\] \[\text{= 70 }\,\text{km + }\frac{\text{5}}{\text{1000}}\,\text{km = (70 + 0}\text{.005) km = 70}\text{.005 km}\]