Page 125 - Fun with Mathematics 2

The point where two or three sides meet is called a vertex. It is denoted by a

capital letter.

Rectangle

The plane surface of a cuboid is called a rectangle. S R

Properties of a rectangle: Rectangle Side
4
A rectangle has sides.
l Vertex
The opposite sides of a rectangle are equal. P Q
l
4
A rectangle has vertices.
l
Triangle A

The plane surface of a cone is called a triangle.

Properties of a triangle: Side

A triangle has 3 sides. Triangle
l
A triangle has 3 vertices. B Vertex
l C
Circle

The plane surface of a cylinder is called a circle.

Properties of a circle: Circle

A circle has no edge and no vertex.
l
The distance from the centre of a circle to any point
l
on the boundary of the circle is always equal.

1 Write ‘Yes’ or ‘No’.

(a) Is the meeting point of two adjacent sides of a plane figure
called vertex? ________

(b) Does a triangle have four sides? ________

(c) Is the name of the vertex usually represented by a small letter? ________

(d) Are the number of the sides of a plane figure with a plane surface
equal to the number of vertices of the figure? ________

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