Q71Written answer
A cylinder has no vertex.
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Worked solution
Ans: No vertex is present in the cylinder.
Therefore, the given statement is True.
NCERT Exemplar · Class 7 · Maths
Chapter 12: Practical Geometry Symmetry and Visualising Solid Shapes
Practice each question, then open the answer or worked solution.
Textbook exercises
124 questionsQ72Written answer
All the faces, except the base of a square pyramid are triangular.
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Ans: The base of a square pyramid is square and the rest of the faces are triangular.
A square pyramid has $4$ triangular faces and one square base.
Therefore, the given statement is True.
Q73Written answer
A pyramid has only one vertex.
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Ans: There are at least four vertices in a pyramid.
Therefore, the given statement is False.
Q74Written answer
A triangular prism has ${\mathbf{5}}$ faces, ${\mathbf{9}}$ edges and ${\mathbf{6}}$ vertices.
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Ans: A triangular prism is a prism that has two triangular bases and three rectangular sides. It has $6$vertices, $9$ edges, and $5$ faces.
Therefore, the given statement is True.
Q75Written answer
If the base of a pyramid is a square, it is called a square pyramid.
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Ans: The name of a pyramid is based on the base of the pyramid.
Thus, if the base of a pyramid is a square, then it is called a square pyramid.
Therefore, the given statement is True.
Q76Written answer
A rectangular pyramid has ${\mathbf{5}}$ rectangular faces.
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Ans: A rectangular pyramid has in total $5$ faces, out of which $1$ is rectangular.
Therefore, the given statement is False.
Q77Written answer
Rectangular prisms and cuboids refer to the same solid.
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Ans: A rectangular prism is also known as a cuboid.
So, a rectangular prism and cuboid represents the same solid.
Therefore, the given statement is True.
Q78Written answer
A tetrahedron has ${\mathbf{3}}$ triangular faces and ${\mathbf{1}}$ rectangular faces.
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Ans: A tetrahedron has $4$ triangular faces.
Therefore, the given statement is False.
Q79Written answer
While a rectangle is a ${\mathbf{2 - D}}$ figure, a cuboid is a ${\mathbf{3 - D}}$ figure.
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Ans: ${\text{2 - D}}$ shapes including rectangles, squares, circles and triangles. ${\text{3 - D}}$ shapes including cubes, cuboids, spheres etc.
Therefore, the given statement is True.
Q80Written answer
While the sphere is a ${\mathbf{2 - D}}$ figure, the circle is a ${\mathbf{3 - D}}$ figure.
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Worked solution
Ans: ${\text{2 - D}}$ shapes including rectangles, squares, circles and triangles. ${\text{3 - D}}$ shapes including cubes, cuboids, spheres etc.
Therefore, the given statement is False.