It covers squares, right-angled triangles, a rhombus, and an equilateral triangle.
The Baudhāyana-Pythagoras Theorem is used with the sides of the square.
The diagonals are halved to form a right triangle.
The hypotenuse is the longest side.
The equilateral triangle has a side length of 6 units.
ALLEN provides detailed solutions for Class 8 Maths Exercise 2.4.
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The Baudhayana-Pythagoras Theorem - Exercise 2.4 Class 8 Maths - Chapter 2 NCERT Solutions
NCERT detailed solutions for Class 8 Maths Term 2 Chapter 2, The Baudhayana-Pythagoras Theorem, Exercise 2.4 are provided on this webpage. Prepared by the experienced ALLEN faculty, these solutions give clear explanations for each question to support students in their exam preparation.In Exercise 2.4, we use the Baudhāyana-Pythagoras Theorem to solve geometric problems involving the diagonal of a square, the unknown sides of right-angled triangles, the side of a rhombus with given diagonals, and the height and area of an equilateral triangle.
1.0Download Class 8 Maths Chapter 2 Ex 2.4 NCERT Solutions PDF
Download the Class 8 Maths Chapter 2 Exercise 2.4 NCERT Solutions PDF for step-by-step solutions and convenient revision. The PDF can be used to practise the questions and review the methods while preparing for exams.
Chapter 2 : The Baudhayana - The Pythagoras Theorem Exercise 2.4
2.0Detailed NCERT Solutions for The Baudhayana-Pythagoras Theorem Exercise 2.4 Class 8 Maths (Ganita Prakash Term 2)
1. Find the diagonal of a square with side length 5 cm.
Sol.
BD2=52+52=25+25=50BD2=50=5×5×2=52=5×1.414=7.07(∼7.1)
Hence, the length of the diagonal is 52 ( 7.1 cm ) approx.
2. Find the missing side lengths in the following right triangles:
3. Find the side length of a rhombus whose diagonals are of length 24 units and 70 units.
Sol.
Since diagonals of Rhombus bisect each other at 90∘.
OA=21×24=12
OD =21×70=35
In △AOD,a2=122+352=144+1225=1369a=1369=37∴ The side of the rhombus is 37 units.
4. Is the hypotenuse the longest side of a right triangle? Justify your answer.
Sol. c2=a2+b2∴c2>a2 and c2>b2
Or c>a and c>b
Hence, 'c' is the longest side of the right triangle.
5. True or False: Every Buadhayana triple is either a primitive triple or a scaled version of a primitive triple.
Sol. Let (a,b,c) be a Baudhayana triple.
Then HCF(a,b,c)1 or HCF(a,b,c)=1(3,4,5):HCF is 1
(10,24,26):HCF=2
If HCF is 1 , then the triple is primitive
If HCF is a number other than 1 , then the triple is scaled.
6. Give 5 examples of rectangles whose side lengths and diagonals are all integers. Sol.
(i)
(ii)
(iii)
(iv)
(v)
7. Construct a square whose area is equal to the difference of the areas of squares of side-lengths 5 units and 7 units.
Sol. To form a square whose area should be
⇒72−52=49−25=24 sq. units.
Now, draw a right angles triangle XYZ such that XY=5cm and YZ=7cm.
Here, XZ2−XY2=ZY2
XZ2=72−52=49−25=24XZ=24cm
Then draw a square XZUV of side length 24cm as shown.
Hence, the square XZUN is formed whose area is equal to difference of area of squares of side lengths 5 units and 7 units.
8. (i) Using the dots of a grid as the vertices, can you create a square that has an area of
(a) 2 sq. units,
(b) 3 sq. units,
(c) 4 sq-units,
(d) 5 unit
(ii) Suppose the grid extends indefinitely. What are the possible integer-values areas of squares you can create in this manner?
Sol. (i) Since, one side of square formed will be hypotenuse 'c' of a right angled triangle formed by the grid lines.
The legs of this triangle will be 'a' units and 'b' units.
Now, c2=a2+b2
Because, the dots are on a grid, a and b must be whole number ( 0,1,2,3,… ). This means that the area of a square on a dot grid must be equal to sum of two perfect square.
(a) Area of 2 square units
Since 2=(1)2+(1)2
So, AP=PD=1 units
⇒AD=AP2+PD2=1−11=2 units
Area of square ABCD=2sq. units
Tilted square ABCD is formed.
(b) Area of 3 sq. units
There is no combination of two perfect square that add up to 3 .
It is impossible to draw a square with an area of 3 sq. units on a standard integer dot grid.
(c) Area of 4 sq. units
∵4=(2)2+02=4+0=4
Non tilted square ABCD is formed.
(d) Area of 5 sq. units 5=(2)2+(1)2 Area of square ABCD=5sq. units Tilted square ABCD is formed.
(ii) If the grid extends indefinitely, the possible integer area are exactly the numbers that can be written as the sum of two perfect squares.
... and so on
Here, 3 , 6 , 7 , 11 , 12 , 14 , 15 are shifted as it is impossible to draw a square on a standard integer dot grid.
9. Find the area of an equilateral triangle with sidelength 6 units.
[Hint: Show that an altitude bisects the opposite side. Use this to find the height.]
Sol. Let △ABC be an equilateral triangle.AB=BC=CA=6cm
Let AD be perpendicular to BC .
Then ∠1=∠2 (each 90∘ )
AB=AC (each 6 cm )
AD=AD (common)
△ADB≅△ADC (by RHS congruency)
BD=DC (CPCT)
∴BD=DC=21×6cm=3cm
In △ADC,h2+32
⇒⇒h=62 (Baudhayana’s triple) h2=36−9=27=ar(ΔABC)=21×BC×AD=21×6×33 sq. units =93 sq. units
3.0Key Concepts of Chapter 2 - The Baudhayana-Pythagoras Theorem Exercise 2.4
Calculating the diagonal of a square with side length 5 cm.
Determining unknown sides in the given right-angled triangles.
Using the diagonals of a rhombus measuring 24 units and 70 units to calculate its side.
Identifying the hypotenuse as the longest side of a right-angled triangle.
Working with an isosceles right triangle with a hypotenuse of 10 units.
Calculating the height and area of an equilateral triangle with side length 6 units.
4.0Benefits of NCERT Solutions Class 8 Maths Chapter 2 Exercise 2.4
Shows the steps for calculating the diagonal of a square.
Makes the calculation of unknown sides in right-angled triangles easier to follow.
Explains how rhombus diagonals are used to calculate its side.
Helps understand the position of the hypotenuse in a right-angled triangle.
Provides the method used for the isosceles right triangle problem.
Explains the calculation of the height and area of the given equilateral triangle.