Question

The total area of the four walls of a hall is 343 sq. m. Its height is 7m. If the floor of
the hall is in the shape of a square, the area of the floor is

(A) 12.25 sq.m
(B) 712 sq.m (C) 150.0625 sq.m (D) 158 sq.m​

Answer 1

Answer:

Mathematics NCERT Grade 8, Chapter 11: Mensuration- This chapter will explain all the concepts of perimeter and area of other plane figures such as quadrilaterals in a comprehensive way. Additionally, emphasis will be laid upon the concept of surface area and volume of solids such as the cube, cuboid, and cylinder. The first half of the chapter covers the following topics:

Area of Trapezium

Area of General Quadrilateral: Area of special quadrilaterals are discussed in brief in this section.

A general quadrilateral can be split into two triangles by drawing one of its diagonals.

Area of rhombus

Area of polygon

Unsolved questions based on the above-cited topics are given in the first two exercises.

In the other half of the chapter, Solid Shapes like cube, cuboid and cylinder are discussed through net diagrams.

The cylinder has congruent circular faces that are parallel to each other. When the line segment joining the centre of circular faces is perpendicular to the base, then such cylinders are known as right circular cylinders.

After that, students will be briefed about the Surface Area of Cube, Cuboid, and Cylinder.

The concept of the Total Surface Area and Lateral Surface Area is also explained.

The side walls (the faces excluding the top and bottom) make the lateral surface area of the cuboid.

The Volume of Cube, Cuboid, and the Cylinder is also explained in the next section by taking a brief example and is supplemented with the appropriate required diagram.

Amount of space occupied by a three-dimensional object is called its volume

The concept of Volume and Capacity is explained with the solved examples.

(a) Volume refers to the amount of space occupied by an object.