In the Maharashtra SSC Board (Class 10), **geometry** plays a significant role in the mathematics syllabus, and theorems are an integral part of this subject. Some key theorems that are important for Class 10 students include:
### 1. **Pythagoras Theorem**
- **Statement**: In a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
- Formula: \( c^2 = a^2 + b^2 \), where \( c \) is the hypotenuse, and \( a \) and \( b \) are the other two sides.
- **Importance**: The Pythagoras theorem is widely used in various problems involving right-angled triangles and is foundational for understanding trigonometry.
### 2. **Thales’ Theorem** (Basic Proportionality Theorem)
- **Statement**: If a line is drawn parallel to one side of a triangle and intersects the other two sides, it divides those two sides in the same ratio.
- **Importance**: This theorem is essential in problems related to similar triangles, proportionality, and geometry constructions.
### 3. **Theorem on Similar Triangles** (AAA Criteria)
- **Statement**: If two angles of one triangle are equal to two angles of another triangle, the triangles are similar.
- **Importance**: This is key for understanding the concept of similarity in triangles and is often used in combination with Thales’ theorem to solve geometric problems.
### 4. **Area Theorems**
- **Statement**: The ratio of the areas of two similar triangles is equal to the square of the ratio of their corresponding sides.
- **Importance**: This theorem is useful when comparing areas of similar shapes and understanding scale factors in geometry.
### 5. **Tangent-Secant Theorem**
- **Statement**: If two secants are drawn from an external point to a circle, the product of the lengths of one secant segment and its external part is equal to the product of the lengths of the other secant segment and its external part.
- **Importance**: It’s crucial for problems involving circles, secants, tangents, and chords.
### 6. **Circle Theorems**
Several theorems related to circles are important:
- **Angle Subtended by an Arc**: The angle subtended by an arc at the center of a circle is twice the angle subtended by the same arc at any point on the remaining part of the circle.
- **Cyclic Quadrilateral Theorem**: The opposite angles of a cyclic quadrilateral sum up to \(180^\circ\).
These theorems form the backbone of the geometry section and are frequently used in problem-solving. Understanding these theorems, their proofs, and applications are essential for scoring well in the SSC Board exams.