myCBSEguide App
Download the app to get CBSE Sample Papers 2023-24, NCERT Solutions (Revised), Most Important Questions, Previous Year Question Bank, Mock Tests, and Detailed Notes.
Install NowNCERT Solutions for Class 8 Maths Exercise 11.2 Class 8 Maths book solutions are available in PDF format for free download. These ncert book chapter wise questions and answers are very helpful for CBSE exam. CBSE recommends NCERT books and most of the questions in CBSE exam are asked from NCERT text books. Class 8 Maths chapter wise NCERT solution for Maths Book all the chapters can be downloaded from our website and myCBSEguide mobile app for free.
CERT solutions for Class 8 Maths Mensuration Download as PDF
NCERT Solutions for Class 8 Maths Mensuration
Class –VIII Mathematics (Ex. 11.2)
NCERT SOLUTION
1.The shape of the top surface of a table is a trapezium. Find its area if its parallel sides are 1 m and 1.2 m and perpendicular distance between them is 0.8 m.
Ans. Here one parallel side of the trapezium = 1 m
And second side = 1.2 m and
height = 0.8 m
Area of top surface of the table
= =
= = 0.88 m2
Hence surface area of the table is 0.88
NCERT Solutions for Class 8 Maths Exercise 11.2
2. The area of a trapezium is 34 and the length of one of the parallel sides is 10 cm and its height is 4 cm.
Find the length of the other parallel side.
Ans. Let the length of the other parallel side be
Length of one parallel side = 10 am and height = 4 cm
Area of trapezium =
Hence another required parallel
side is 7 cm.
3. Length of the fence of a trapezium shaped field ABCD is 120 m. If BC = 48 m, CD = 17 m and AD = 40 m, find the area of this field. Side AB is perpendicular to the parallel sides AD and BC.
Ans. Given: BC = 48 m, CD = 17 m,
AD = 40 m and perimeter = 120 m
Perimeter of trapezium ABCD
= AB + BC + CD + DA
120 = AB + 48 + 17 + 40
120 = AB = 105
AB = 120 – 105 = 15 m
Now Area of the field
=
=
=
= 660
Hence area of the field ABCD is 660.
NCERT Solutions for Class 8 Maths Exercise 11.2
4. The diagonal of a quadrilateral shaped field is 24 m and the perpendiculars dropped on it from the remaining opposite vertices are 8 m and 13 m. Find the area of the field.
Ans. Here = 13 m, = 8 m and
AC = 24 m
Area of quadrilateral ABCD
= Area of ABC + Area of ADC
=
=
=
=252
Hence required area of the field
is 252
5. The diagonals of a rhombus are 7.5 cm and 12 cm. Find its area.
Ans. Given: =7.5 cm and = 12 cm
We know that,
Area of rhombus =
=
= 45
Hence area of rhombus is 45 .
6. Find the area of a rhombus whose side is 6 cm and whose altitude is 4 cm. If one of the diagonals is 8 cm long, find the length of the other diagonal.
Ans. Since rhombus is also a kind of parallelogram.
Area of rhombus
= Base Altitude
= 6 4 = 24
Also Area of rhombus =
24 =
= 6 cm
Hence the length of the other
diagonal is 6 cm.
NCERT Solutions for Class 8 Maths Exercise 11.2
7. The floor of a building consists of 3000 tiles which are rhombus shaped and each of its diagonals are 45 cm and 30 cm in length. Find the total cost of polishing the floor, if the cost per is ` 4.
Ans. Here, = 45 cm and = 30 cm
Area of one tile =
= = 675
Area of 3000 tiles
= 675 3000 = 2025000
=
= 202.50
Cost of polishing the floor per
sq. meter = 4
Cost of polishing the floor per 202.50 sq. meter = 4 202.50 = 810
Hence the total cost of polishing the floor is 810.
NCERT Solutions for Class 8 Maths Exercise 11.2
8. Mohan wants to buy a trapezium shaped field. Its side along the river is parallel to and twice the sidealong the road. If the area of this field is 10500 m2 and the perpendicular distance between the two parallel sides is 100 m, find the length of the side along the river.
Ans. Given: Perpendicular distance
= 100 m
Area of the trapezium shaped field
= 10500
Let side along the road be m and side along the river = m
Area of the trapezium field
=
10500 =
m
Hence the side along the river =
= 2 70 = 140 m.
NCERT Solutions for Class 8 Maths Exercise 11.2
9. Top surface of a raised platform is in the shape of a regular octagon as shown in the figure. Find the area of the octagonal surface.
Ans. Given: Octagon having eight equal sides, each 5 m.
Construction: Divided the octagon in 3 figures, two trapeziums whose parallel and perpendicular sides are 11 m and 4 m respectively and third figure is rectangle having length and breadth 11 m and 5 m respectively.
Now Area of two trapeziums = 2 x
= 2 = 4 16 = 64
And Area of rectangle = length breadth
= 11 5 = 55
Total area of octagon = 64 + 55
= 119
NCERT Solutions for Class 8 Maths Exercise 11.2
10. There is a pentagonal shaped park as shown in the figure.
For finding its are a Jyoti and Kavita divided it in two different ways.
Find the area of this park using both ways. Can you suggest some other way of finding its area?
Ans. First way: By Jyoti’s diagram,
Area of pentagon = Area of trapezium ABCP + Area of trapezium AEDP
= (AP + BC) x CP + (ED + AP) DP = (30 + 15 ) x CP + (15 + 30) DP
= (30 + 15) (CP + DP)
= 45 CD
=337.5 m2
Second way:
By Kavita’s diagram
Here, a perpendicular AM drawn to BE.
AM = 30 – 15 = 15 m
Area of pentagon
= Area of ABE + Area of square BCDE
=1515+1515m
= 112.5 + 225.0
= 337.5 m2
Hence total area of pentagon shaped
park = 337.5.
NCERT Solutions for Class 8 Maths Exercise 11.2
11. Diagram of the adjacent picture frame has outer dimensions = 24 cm 28 cm and inner dimensions 16 cm 20 cm. Find the area of each section of theframe, if the width of each section is same.
Ans. Here two of given figures (I) and (II) are similar in dimensions.
And also figures (III) and (IV) are similar in dimensions.
Area of figure (I) = Area of trapezium
=
=
=
= 96
Also Area of figure (II) = 96 cm2
Now Area of figure (III)
= Area of trapezium =
= = = 80
Also Area of figure (IV) = 80
NCERT Solutions for Class 8 Maths Exercise 11.2
NCERT Solutions Class 8 Mathematics PDF (Download) Free from myCBSEguide app and myCBSEguide website. Ncert solution class 8 Mathematics includes text book solutions from Class 8 Maths Book . NCERT Solutions for CBSE Class 8 Maths have total 16 chapters. 8 Maths NCERT Solutions in PDF for free Download on our website. Ncert class 8 solutions PDF and Maths ncert class 8 PDF solutions with latest modifications and as per the latest CBSE syllabus are only available in myCBSEguide.
CBSE app for Class 8
To download NCERT Solutions for class 8 Social Science, Computer Science, Home Science,Hindi ,English, Maths Science do check myCBSEguide app or website. myCBSEguide provides sample papers with solution, test papers for chapter-wise practice, NCERT solutions, NCERT Exemplar solutions, quick revision notes for ready reference, CBSE guess papers and CBSE important question papers. Sample Paper all are made available through the best app for CBSE students and myCBSEguide website.
Test Generator
Create question paper PDF and online tests with your own name & logo in minutes.
Create NowmyCBSEguide
Question Bank, Mock Tests, Exam Papers, NCERT Solutions, Sample Papers, Notes
Install Now
Worst sums ever huh those are all wrong answers never see in this site
this site is very good way to learn math
This is very work
In excercise 11.2 the 6th questions is given wrong it is 4.8 cm but here it is 4cm
Plz clear my doubt
Samma it is really a useful app I like this app bcoz it is used for education
IT IS VERY USEFUL TWO UNDERSTAND ACCEPT FEW I THINK SOME SOLUTIONS SHOULD BE ELABORATE NICELY
GUD WAY OF LEARNING BUT SHOUD ELABORATE SOME SOLUTION NICELY
Very very nice way of studying thanks also put the chapter no 13 of class 8 please
Its very use full
Good aap
i love this app
Good app
Please solve examples also
Helpful?
Thank you it is very easy
It is very use full to us thank you NCERT Guide
Nice solution
nice
Nice
Solution
Very nice solution
I like it very much but