Here's a table with some topic-related information regarding the "Selina Class 9 Maths Solutions" to provide a better understanding for students:
| Topic |
Concept |
Key Formula/Method |
Importance in Class 9 |
| Algebra |
Simplifying expressions, solving equations |
3x + 2 = 8, x = (8 - 2)/3 |
Essential for solving linear equations and inequalities |
| Geometry |
Properties of shapes, angles, area, perimeter |
Area = l × b (rectangle), A = ½ × b × h (triangle) |
Helps understand the properties of 2D and 3D shapes |
| Trigonometry |
Ratios of angles, sine, cosine, tangent |
sin(θ) = opposite/hypotenuse |
Important for solving angle-related problems and applications in real life |
| Statistics |
Mean, median, mode, probability |
Mean = (Sum of all data points) / (Number of data points) |
Key for analyzing data and interpreting results |
| Mensuration |
Surface area and volume of solids |
Volume = πr²h (cylinder), Surface Area = 6a² (cube) |
Critical for understanding space, dimensions, and measurements |
| Quadratic Equations |
Solving quadratic equations |
ax² + bx + c = 0, use of factorization or quadratic formula |
Key topic for higher-level algebraic concepts |
| Linear Equations |
Solving for variables in linear form |
y = mx + b (slope-intercept form) |
Fundamental for understanding graphs and functions |
This table summarizes essential topics and methods from the Class 9 Selina Maths solutions, making it easier for students to review key concepts and understand their importance for both exams and practical application.
Question 1:
Question: What is the value of √(64)?
Answer: The value of √(64) is 8.
Question 2:
Question: Simplify: 5x + 3x.
Answer: The simplified expression is 8x.
Question 3:
Question: What is the perimeter of a rectangle with length 6 cm and width 4 cm?
Answer: The perimeter of the rectangle is 20 cm.
Question 4:
Question: Find the area of a circle with a radius of 7 cm.
Answer: The area of the circle is 154 cm² (πr²).
Question 5:
Question: If a triangle has sides 3 cm, 4 cm, and 5 cm, is it a right-angled triangle?
Answer: Yes, the triangle is a right-angled triangle.
Question 6:
Question: Solve for x: 3x + 4 = 10.
Answer: x = 2.
Question 7:
Question: What is the value of π?
Answer: The value of π is approximately 3.1416.
Question 8:
Question: Simplify: 2a - 3a + 4.
Answer: The simplified expression is -a + 4.
Question 9:
Question: What is the sum of the angles of a triangle?
Answer: The sum of the angles of a triangle is 180°.
Question 10:
Question: What is the formula for the area of a rectangle?
Answer: The formula for the area of a rectangle is length × width.
Question 11:
Question: Find the value of 2/3 + 5/6.
Answer: The sum of 2/3 + 5/6 is 7/6 or 1 1/6.
Question 12:
Question: What is the value of 15% of 200?
Answer: 15% of 200 is 30.
Question 13:
Question: Simplify: 4x - 2x + 3y - 4y.
Answer: The simplified expression is 2x - y.
Question 14:
Question: What is the formula for the area of a triangle?
Answer: The formula for the area of a triangle is (1/2) × base × height.
Question 15:
Question: If the radius of a circle is 14 cm, what is its circumference?
Answer: The circumference of the circle is 87.92 cm (2πr).
Question 16:
Question: Solve for x: 5x - 7 = 3x + 5.
Answer: x = 6.
Question 17:
Question: Find the value of (x + 3)(x - 4).
Answer: The value of (x + 3)(x - 4) is x² - x - 12.
Question 18:
Question: What is the LCM of 6 and 8?
Answer: The LCM of 6 and 8 is 24.
Question 19:
Question: What is the HCF of 18 and 24?
Answer: The HCF of 18 and 24 is 6.
Question 20:
Question: Solve for x: 2x + 5 = 17.
Answer: x = 6.
Question 21:
Question: What is the volume of a cube with a side length of 5 cm?
Answer: The volume of the cube is 125 cm³.
Question 22:
Question: Simplify: 3a² - 4a + 5a².
Answer: The simplified expression is 8a² - 4a.
Question 23:
Question: Find the distance traveled by an object moving at 20 m/s for 5 seconds.
Answer: The distance traveled is 100 meters (speed × time).
Question 24:
Question: What is the formula for the surface area of a sphere?
Answer: The formula for the surface area of a sphere is 4πr².
Question 25:
Question: Simplify: 7x + 3x - 4y.
Answer: The simplified expression is 10x - 4y.
Question 26:
Question: Find the square root of 121.
Answer: The square root of 121 is 11.
Question 27:
Question: What is the formula for the volume of a cylinder?
Answer: The formula for the volume of a cylinder is πr²h.
Question 28:
Question: What is the difference between an arithmetic sequence and a geometric sequence?
Answer: In an arithmetic sequence, each term differs by a constant difference, while in a geometric sequence, each term is multiplied by a constant ratio.
Question 29:
Question: Find the area of a square with a side length of 9 cm.
Answer: The area of the square is 81 cm².
Question 30:
Question: What is the formula for the Pythagorean theorem?
Answer: The formula for the Pythagorean theorem is a² + b² = c².
Question 31:
Question: Solve for x: 4x + 5 = 2x + 9.
Answer: x = 2.
Question 32:
Question: What is the area of a triangle with a base of 10 cm and height of 8 cm?
Answer: The area of the triangle is 40 cm².
Question 33:
Question: What is the product of 5 and 7?
Answer: The product of 5 and 7 is 35.
Question 34:
Question: What is the sum of the first 10 natural numbers?
Answer: The sum of the first 10 natural numbers is 55.
Question 35:
Question: What is the value of 4² + 3²?
Answer: The value of 4² + 3² is 16 + 9 = 25.
Question 36:
Question: Solve for x: 3x - 6 = 12.
Answer: x = 6.
Question 37:
Question: What is the formula for the area of a parallelogram?
Answer: The formula for the area of a parallelogram is base × height.
Question 38:
Question: Find the square root of 49.
Answer: The square root of 49 is 7.
Question 39:
Question: What is the volume of a cone with radius 5 cm and height 10 cm?
Answer: The volume of the cone is 261.8 cm³ (1/3πr²h).
Question 40:
Question: What is the difference between a rational number and an irrational number?
Answer: A rational number can be written as a fraction, while an irrational number cannot be written as a fraction.
Question 41:
Question: Simplify: 3x² - 2x² + 5x - 3x.
Answer: The simplified expression is x² + 2x.
Question 42:
Question: What is the surface area of a cuboid with length 4 cm, width 3 cm, and height 5 cm?
Answer: The surface area of the cuboid is 94 cm².
Question 43:
Question: What is the formula for the volume of a rectangular prism?
Answer: The formula for the volume of a rectangular prism is length × width × height.
Question 44:
Question: Solve for x: 2x - 3 = 7.
Answer: x = 5.
Question 45:
Question: What is the LCM of 4, 6, and 8?
Answer: The LCM of 4, 6, and 8 is 24.
Question 46:
Question: What is the area of a rhombus with diagonals of 6 cm and 8 cm?
Answer: The area of the rhombus is 24 cm² (1/2 × d₁ × d₂).
Question 47:
Question: What is the perimeter of an equilateral triangle with side length 7 cm?
Answer: The perimeter of the equilateral triangle is 21 cm.
Question 48:
Question: Find the sum of the angles in a quadrilateral.
Answer: The sum of the angles in a quadrilateral is 360°.
Question 49:
Question: What is the formula for the surface area of a cube?
Answer: The formula for the surface area of a cube is 6a², where a is the side length.
Question 50:
Question: Find the value of (x + 2)(x + 5).
Answer: The value of (x + 2)(x + 5) is x² + 7x + 10.