Page 86 - Maths Class 06
P. 86
(g) Triangular pyramid
(h) Square pyramid
2. Match the follow ing:
Shapes Objects
(a) Sphere (i) A coke can
(b) Cylinder (ii) A cricket ball
(c) Cuboid (iii) A dice
(d) Cube (iv) A chalk duster
3. Write the number of triangles in the nets of:
(a) Triangular prism (b) Square pyramid
4. Draw the trian gular prism and its net.
At a Glance
l A line segment has two end points, the length of the line segment can be determined using the ruler
and the divider.
l When two rays meet at a common endpoint, they form an angle. An angle is acute, if its measure is
less than 90° and is obtuse, if its measure is more than 90° and less than 180°. The measures of right
angle and straight angle are 90° and 180° respectively. A reflex angle is always larger than a straight
angle and is less than a complete angle.
l The East is at right angle to the North in clockwise direction and West is at right angle to the North in
anticlockwise direction. The turn from North to South is by 2 right angles.
l The clock hand moves two straight angles to complete one turn. One complete turn (revolution) is
divided in 360 equal parts (degree).
l If the angle formed by intersection of two lines is right angle then the lines are said to be
perpendicular. Symbol ‘ ’^ denotes the perpendicularity.
l The triangles can be classified in three ways, on the basis of their angles:
Acute-angled triangle (each angle is less than 90°), obtuse-angled triangle (one angle is obtuse) and
right-angled triangle (one angle is 90°).
l On the basis of their sides, triangles can again be classified in three ways :
Scalene triangle (All sides are different), Isosceles triangle (two sides are equal) and Equilateral
triangle (all sides are equal).
l Polygons can be named on the basis of the number of sides they have. A three sided polygon is a
triangle. A four sided polygon is a quadrilateral. A five sided polygon is a pentagon. A six, seven and
eight sided polygons are known as a hexagon, heptagon and octagon respectively.
l Quadrilaterals can be mainly classified as parallelogram, rectangle, square, rhombus, and trapezium.
All these quadrilaterals have different properties for their identification.
86
