Question
Area of a square is $$\left( {100 \pm 2} \right){m^2}.$$ Its side is
A.
$$\left( {10 \pm 1} \right)m$$
B.
$$\left( {10 \pm 0.1} \right)m$$
C.
$$\left( {10 \pm \sqrt 2 } \right)m$$
D.
$$10 \pm \sqrt 2 \% $$
Answer :
$$\left( {10 \pm 1} \right)m$$
Solution :
$$\eqalign{
& {\text{Area}} = {\left( {{\text{Length}}} \right)^2} \cr
& {\text{or}}\,{\text{length}} = {\left( {{\text{Area}}} \right)^{\frac{1}{2}}} = {\left( {100 \pm 2} \right)^{\frac{1}{2}}} \cr
& = {\left( {100} \right)^{\frac{1}{2}}} \pm \frac{1}{2} \times 2 \cr
& = \left( {10 \pm 1} \right)m \cr} $$