The circumference of the spherical shaped coconut below is $37.052 \mathrm{cm}.$ The thickness of the shell including the edible part is $2 \mathrm{cm}.$

Estimate the amount of coconut water inside it, if it constitutes $60\%$ of its inner volume.

 

Which of these is the closest estimate of the amount of coconut water in the coconut?

Shyam is assigned a project for which he needs to make an electromagnet. To make an electromagnet a copper wire with diameter $3 \mathrm{mm}$ is wound to cover the curved surface area of the iron core cylinder, whose length is $12 \mathrm{cm}$ and diameter is $6 \mathrm{cm}$.

What is mass of the copper wire if its density of copper is $8.9 \mathrm{g}/\mathrm{cc}$ ?

Below is the picture of an open well $42 \mathrm{ft}$ deep and diameter $28 \mathrm{ft}$. The well needs to be plastered, and $50 \mathrm{kg}$ cement is required to plaster $300 {\mathrm{ft}}^2$. 

How much cement is required to plaster the wall of the well from top to bottom?

The height of the tent in the picture below is $3 \mathrm{m}$ and its circumference is $25.12 \mathrm{m}$. 

What is the minimum area of the canvas needed to make the tent? (Take $\mathrm{\pi }=3.14$)

Kiran took a circular piece of tin of radius $25 \mathrm{cm}$ and he removed a sector of tin of angle $144°$. He folded the remaining piece of tin into a cone (without a gap or overlap) such that the centre of the sector becomes the vertex of the cone, as shown in the figure below. Kiran then filled the cone with water.

How much water did he need to fill the cone completely?

Below is a spherical-shaped tent (not a hemisphere) made of canvas. It has a height of $8 \mathrm{ft}$ and floor radius $12 \mathrm{ft}$. The curved surface area of the dome is given by the formula, $2\mathrm{\pi }rh$, where $h$ is height of the dome and $r$ is the radius of curvature of the dome.

Find the minimum area of canvas required to make the tent.

Kirti took a watermelon of circumference $44 \mathrm{cm}$ and then cut out a piece, which is roughly $\frac{1}{8}$ of the watermelon. 

Estimate the area of the skin of the smaller piece.