NCERT Solutions Ganita Prakash Chapter 4 Figure it Out — Artistic and Aesthetic Considerations (2026-27)

Q1.

If you wanted to visually represent the data of the heights of the tallest persons in each class in your school, would you use a graph with vertical bars or horizontal bars? Why?

Answer

Vertical bars (a column graph).

Why: a person's height is measured upward from the ground. A vertical bar also grows upward from the base line, so the picture works the same way as the thing it stands for. The reader compares the tops of the columns exactly as they would compare children standing side by side against a wall — and understands it without being told.

Two more practical reasons:

The class names (Class 1, Class 2, … Class 8) are short, so they fit neatly under the columns.
All the heights lie close together — say 120 cm to 165 cm — and it is easier to see small differences between the tops of upright columns.

A horizontal bar graph would also be correct mathematically — the numbers do not change. It would simply look less natural, as if the children were lying down.

Tip: whichever you choose, start the scale at 0. If you start the scale at 100 cm to “save space”, a child of 150 cm will appear to be twice as tall as one of 125 cm, which is not true.

Q2.

If you were making a table of the longest rivers on each continent and their lengths, would you prefer to use a bar graph with vertical bars or with horizontal bars? Why? Try finding out this information, and then make the corresponding table and bar graph! Which continents have the longest rivers?

Answer

Horizontal bars.

Why: the length of a river is measured along the ground, not upward. A horizontal bar lies along the ground in the same way, so it suggests a river flowing across the land. It also leaves plenty of room on the left for long names like “Mississippi–Missouri”, which would have to be squeezed or turned sideways under a vertical column.

Here is the table, with lengths rounded to the nearest ten kilometres:

Continent	Longest river	Length (approx.)
Africa	Nile	6650 km
South America	Amazon	6400 km
Asia	Yangtze	6300 km
North America	Mississippi–Missouri	6275 km
Australia	Murray–Darling	3670 km
Europe	Volga	3530 km
Antarctica	Onyx	32 km

The longest river of each continent, drawn as horizontal bars — the shape of the picture matches the shape of a river.

Which continents have the longest rivers? Africa (the Nile) and South America (the Amazon) — with Asia's Yangtze and North America's Mississippi–Missouri very close behind. The top four are almost equal; then comes a big drop to Australia and Europe, and Antarctica's Onyx is tiny because it is frozen for most of the year.

Nile − Volga = 6650 − 3530 = 3120 km
Nile ÷ Onyx ≈ 6650 ÷ 32 ≈ 208 times as long

Did you know? India's longest river, the Ganga, is about 2525 km long. Drawn on the same graph, its bar would be a little shorter than two-fifths of the Nile's bar.