solve the all question of section A
Answers
Section - A
1) Write the nature of decimal expansion of √2
Answer : Since, √2 is irrational, It's decimal expansion is Non Terminating, Non recurring.
2) Factorise x² - 16
Answer :
3) Cost of a pen is two and half times the cost of pencil.
Let the cost of pen be x
Let the cost of pencil be y
ATQ, x = 5/2 y
2x - 5y = 0
4) Here, Mohan age = John age
Mohan age= Ram age.
So, By Euclid first axiom, Things equal to the same thing are equal to one another.
5) base = 35cm
Area = 420 cm²
Height =
Height = 12cm.
6) Surface area = Volume of the cube
6a² = a³
This implies, a = 6.
Therefore, Edge of the cube is 6 units.
1. we know that √2 is an irrational number and decimal expansion of an irrational number is non-terminating and non-recurring. therefore the nature of the decimal expansion of √2 is non-terminating and non-recurring.
2. given :- x² - 16
x² can be written as = (x)² [since (x)² = x * x = x²)
similarly, 16 = (4)²
= (x)² - (4)²
by using identity a² - b² = (a - b) (a + b)
final answer = (x - 4) (x + 4)
3. ATQ, the cost of a pen is 2 ½ times of a pencil.
let the cost of pencil be x.
and cost of pen be y.
y = 2 ½ of x
y = 2 × ½ × x
y = 5/2 × x
2y = 5x
➡ 2y - 5x = 0 (final ans)
4. ATQ, John is of the same age of Mohan and Ram is also of the same age of Mohan.
according to Euclid's axiom, things which are equal to same things are equal to one another.
from this axiom, we can conclude that John's age = Ram's age
5. given the base of the triangle = 35cm.
area of the triangle = 420cm²
formula for the area of a triangle is 1/2 × b × h
therefore 1/2 × b × h = 420cm²
➡ 1/2 × 35 × h = 420cm²
➡ 35 × h = 420 × 2
➡ 35 × h = 840
➡ h = 840/35
➡ h = 24cm
hence, the altitude of the triangle is 24cm.
6. ATQ, a cube has numerically equal volume and surface area.
formula for the surface area of a cube = 6a² (a = edge of the cube)
formula for the volume of a cube = a³
➡ 6a² = a³
➡ 6 = a³/a²
➡ a = 6
hence, the edge of the cube is 6.