Precision and Significant Figures

The number of significant figures for the three number $161\mathrm{cm}, 0.161\mathrm{cm}, 0.0161\mathrm{cm}$  are:

The side of a cube is measured by vernier callipers ($10$ divisions of a vernier scale coincide with $9$ divisions of main scale, where $1$ division of main scale is $1 \mathrm{mm}$ ). The main scale reads $10 \mathrm{mm}$ and first division of vernier scale coincides with the main scale. Mass of the cube is $2.736 \mathrm{g}$. Find the density of the cube in appropriate significant figures.

The side of a cube is measured by vernier calipers ($10$ divisions of a vernier scale coincide with $9$ divisions of main scale, where $1$ division of main scale is $1 \mathrm{mm}$). The main scale reads $10 \mathrm{mm}$ and first division of vernier scale coincides with the main scale. Mass of the cube is $2.736 g$. Find the density of the cube in appropriate significant figures.

The answer of $(1.0236-0.97268)$ with due regards to significant figure is

For the four sets of three measured physical quantities as given below. Which of the following options is correct?
$\left(i\right)$ $A_1=24.36,B_1=0.0724,C_1=256.2$
$\left(ii\right)$ $A_2=24.44,B_2=16.082,C_2=240.2$
$\left(iii\right)$ $A_3=25.2,B_3=19.2812,C_3=236.183$
$\left(iv\right)$ $A_4=25,B_4=236.191,C_4=19.5$

The area of a circle is $20 {\text{cm}}^2$. Calculate the radius of the circle correct to $2$ significant figures. $\left(\text{use }\mathrm{\pi }=3.14\right)$

A circle has radius $33 \text{cm}$. Calculate the circumference of the circle to $3$ significant figures. $\left(\text{use }\mathrm{\pi }=3.14\right)$

Round the number $\sqrt{62}$ to $1$ decimal places.

Round the number $0.00637$ to $2$ significant figures.

Round the number $27318$ to $1$ significant figure.

Round the number$3.749$  to $3$ significant figures.

Round the number $8888$ to $3$ significant figures.

Round the number $6.999$ to $2$ decimal places.

Round the number $1.8055$ to $2$ decimal places.

Round the number $5.322$ to $2$ decimal places.

Round the number $9.478$ to $2$ decimal places.

Determine the number of significant figures in $1000000 \text{μg}$.

Determine the number of significant figures in $0.001020 \text{km}$.

Determine the number of significant figures in $105 \text{kg}$.