# Important Questions for Class 8 Chapter 10-Visualizing Solid Shapes

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Important questions based on NCERT syllabus for Class 7 Class 8 Chapter 10 - Visualising Solid Shapes:

Question 1: Vijay is going to home from school. He moved 2 km north direction, 3Km in east direction, 5 km in south direction and at last he moved 3 km in west direction. Draw the road map using a proper scale and find the actual distance of his home from school.
Solution:
Take a scale 1 km = 1cm

From the road map we see that distance between school and home = 3 cm
By scale, the distance between school and home = 3 Km

Question 2: What is a regular polyhedron? A cube is a regular polyhedron but cuboid is not a regular polyhedron. Why?
Solution:
A polyhedron is said to be a regular polyhedron if its faces are made up of regular polygons and the same number of faces meet at each vertex.

A cube is a regular polyhedron since it is made of 6 squares which are congruent, but a cuboid is not a regular polyhedron since its faces are not congruent rectangles.

Question 3: Can a polyhedron have 10 faces, 20 edges and 15 vertices? Justify you answer.
Solution:
By Euler's formula,
F + V - E = 2
Substituting the given values
10 + 15 - 20 = 35 - 20 =15 which is not equal to 2
Any solid to be called as polyhedron need to satisfy the Euler's formula.
⇒ A polyhedron cannot have 10 faces, 20 edges and 15 vertices.

Question 4: Fill the missing numbers in the table:

Solution:
From Euler’s formula we know that
F + V - E = 2
In first column,
F+8−12=2
⇒F=6
In second column,
9+V−16=2,
⇒V=9
In third column,
20+V−30=2,
⇒V=12