Unit 7
Unit-7:Mensuration
(a) Area of Trapezium, polygons
(b) Area of general quadrilaterals
(c) Circles
Q1.
3 decimeter is equal to ___________ centimeter
(a) 10 (b) 30 (c) 20 (d) 25
Solution.
(b) 30
Solution
Q2.
Find the side of the equilateral triangle whose area is 16√3 cm2
(a) 5 cm (b) 4 cm (c) 8 cm (d) 3 cm
Solution.
area of triangle = a2√3/4
16√3 = a2√3/4
a = 8
Solution
Q3.
Find the altitude of a triangle whose area is 90 cm2 and base 30 cm.
(a) 6 (b) 4 (c) 5 (d) 3
Solution.
(a) 6
Solution
Q4.
The area of a rhombus is 180 sq cm. one of its diagonals is 40 cm. find the other diagonal.
(a) 10 (b) 4 (c) 6 (d) 8
Solution.
Area of a rhombus = 1/2 x product the diagonal
160 = 1/2 x 40 x d
320 = 40d
d = 8
Solution
Q5.
Find the area of trapezium if its sum of parallel sides are 88cm and it height is 90cm.
(a) 3960 cm2 (b) 2640 cm2
(c) 1800 cm2 (d) 9200 cm2
Solution.
(a) 3960 cm2
Solution
Q6.
Find the circumference of a circle if radius is 2 cm.
(a) 4π (b) 6π (c) π (d) 3π
Solution.
(a) 4π
Solution
Q7.
The area of a square is 121 cm2. If the same wire is bent in the form of circle, find the area of the circle.
(a) 170 cm2 (b) 164 cm2 (c) 154 cm2 (d) 180 cm2
Solution.
Side of a square is 11,
So perimeter of square is 44
2πr = 44
2 x 22/7 x r = 44
r = 7 cm
Area of the circle = πr2 = 154
Solution
Q8.
What is the radius of a circle whose area is 36π .
(a) 10 (b) 6 (c) 3 (d) 5
Solution.
(b) 6
Solution
Q9.
What is the area of a quadrant of a circle of radius 4r.
(a) 3πr2 (b) r2 (c) 4π (d) 4πr2
Solution.
Area of circle = πr2
= π(4r2) = 16πr2
Area of a quadrant = 16πr2/4
= 4πr2
Solution
Q10.
Find the side of a cube if its Total surface area is 36 cm2
(a) 1 (b) 2 (c) √6 (d) 3
Solution.
6a2 = 36
a2 = 6
a = √6
Solution
