Q1: All equilateral triangle are isosceles, but all isosceles triangle are not equilateral. Justify the statement.
Ans: An isosceles triangle is any triangle with 2 sides that are equal in length. So every equilateral triangle is a special case of an isosceles triangle since not just 2 sides are equal, but all 3 are. But every isosceles triangle is not equilateral, because you can have 2 sides of equal length and a third side that is either longer or shorter than those 2 sides. For example, if the triangle is a rightangle triangle and the two sides that meet to make the right angle are the same length, then the 3rd side would be longer than those two.
Q2: Draw a rough sketch of a regular octagon. Draw a rectangle by joining exactly four of the vertices of the octagon.
Ans:
Q3: Draw a hexagon and write its sides and diagonals?
Ans: Hexagon
Sides of hexagon: AB, BC, CD, DE, EF and FA.
Diagonals of hexagon: AC, AD, AE, BD, BE, BF, CE, CF, and DF
Q4: How many faces a tetrahedron have?
Ans: In geometry, a tetrahedron is a polyhedron composed of four triangular faces, three of which meet at each corner or vertex.
Q5: Fill up the following:
(a) Measure of a complete angle is ____________^{o}.
(b) The triangle in which ____________ sides are equal is called isosceles triangle.
(c) Each of its angles rectangle measures ____________^{o}.
(d) A cube has ____________ vertices.
Ans: (a) 360
(b) two
(c) 90
(d) 8
Q6: How do we write symbolically?
Ans:
Q7: What fraction of a clockwise revolution does the hour hand of a clock turn through, when it goes from 12 to 3?
Ans: In clock hour hand moves 12 hr from 12 o’ clock to 12 o’ clock. Fro12 to it 3 it is 3 hr, so fraction of 3 hr from 12 hr = 3/12 = 1/4. Or, the hour hand moves 360^{o} form 12 to 12, from 12 to 3 it moves 90^{o}, so fraction of 90o from 360^{o} = 90/360 = 1/4.
Q8: How many right angles do you make if you start facing south and turn clockwise to west?
Ans: The four main direction north, east, south, west. Each of them are at 90^{o} clockwise, i.e. we have to move 90^{o} to move north to east, another 90^{o} from east to south like that. So South to west we have to move only one 90^{o}. So answer is 1.
Q9: Measure the angles given below, using the Protractor and write down the measure.
Ans: (a) 45°
(b) 125°
(c) 90°
(d) ∠1 = 40°, ∠2 = 125° and ∠3 = 95°.
Q10: If B is the mid point ofwhere A, B, C, D lie on a straight line, say why AB = CD?
Ans:
In view of (1) and (2), we get
AB = CD.
Q11: What is the angle name for half a revolution?
Ans: Straight Angle (180°)
Q12: State true or false:
(a) Sum of any two sides of a triangle is greater than the third side.
(b) An equilateral triangle is also considered as an isosceles triangle
(c) A polygon is regular if its all sides are equal.
(d) Opposite faces of a cuboid are equal in size.
Ans: (a) True
(b) False; in isosceles triangle only two sides are equal.
(c) False; For a polygon to be regular, all sides as well as all angles have to be equal.
(d) True
Q13: Match the following 3D shape and its edges.
Ans:
Q14: What is the angle name for half a revolution?
Ans: One revolution = 360^{o}
Half revolution
180^{o} is called straight angle
Q15: Find the number of right angles turned through by the hour hand of a clock when it goes from 3 to 6.
Ans: Hour hand move 360^{o} from 12 to 12. So it moves 3 hr from 3 to 6. The factor of 3 to 12 = 3/12 = 1/4
Right angle = 90^{o} , factor of 90^{o} with 360^{o }= 90/360 = 1/4.
So Hour hand will turn one right angle to cross 3 to 6.
94 videos347 docs54 tests


Explore Courses for Class 6 exam
