Here’s a summary of the properties of triangles typically covered in ICSE Class 7 Mathematics:

1. **Sum of Angles:** The sum of the three interior angles of a triangle is always 180 degrees.

2. **Exterior Angle:** The exterior angle of a triangle is equal to the sum of the two interior opposite angles.

3. **Types of Triangles:**
– **Equilateral Triangle:** All three sides are equal, and all three angles are equal to 60 degrees.
– **Isosceles Triangle:** Two sides are equal, and two angles are equal.
– **Scalene Triangle:** No sides are equal in length, and no angles are equal in measure.

4. **Pythagorean Theorem:** In a right-angled triangle, the square of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides.

5. **Altitude of a Triangle:** An altitude is a line segment from a vertex perpendicular to the opposite side. All three altitudes intersect at a single point called the orthocenter.

6. **Median of a Triangle:** A median is a line segment from a vertex to the midpoint of the opposite side. All three medians intersect at a single point called the centroid, which divides each median into two segments in a 2:1 ratio.

7. **Angle Bisectors:** An angle bisector is a line segment that divides an angle into two equal parts. All three angle bisectors intersect at a single point called the incenter, which is equidistant from the sides of the triangle.

These concepts form the foundational understanding of triangles in geometry and are essential for further study in mathematics.