Boundaries of solids are
a. surfaces
b. curves
c. lines
d. points

Solution:

We know that

Boundaries of solids are known as surfaces whereas boundaries of surfaces are known as curves.

Therefore, the boundaries of solids are surfaces.

✦ Try This: Prathap and Kishan have the same weight. If they each gain weight by 7 kg, how will their new weights be compared ?

Given, Prathap and Kishan have the same weight.

We have to compare their new weights when each of them gains 7kg.

Let the weight of Prathap be x kg

So, weight of Kishan = x kg

When each gain weight by 7kg,

Weight of Prathap = (x + 7) kg

Weight of Kishan = (x + 7) kg

Using Euclid’s second axiom,

If equals are added to the equals, the wholes are equal.

From the Euclid’s axiom,

(x + 7) = (x + 7)

Therefore, the weight of Prathap is equal to the weight of Kishan.

☛ Also Check: NCERT Solutions for Class 9 Maths Chapter 5

NCERT Exemplar Class 9 Maths Exercise 5.1 Problem 7

Boundaries of solids are a. surfaces, b. curves, c. lines, d. points

Summary:

Solid shapes are three-dimensional shapes that have length, breadth, and height as the three dimensions. Boundaries of solids are surfaces

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