**Exercise 12.2**

**1.Total number of parts of a triangle is**

Soln:(b) 6

Three sides and three angles

**2.A perpendicular drawn from a vertex to the opposite side of a triangle is known as**

Soln:(a) An altitude

An altitude is defined as the perpendicular drawn from a vertex to the opposite side of a triangle.

**3.A triangle**

Soln:(c) has three altitudes

**4.**Line** segment joining the vertices to the **mid â€“ points** of the opposite side of a triangle is known as.**

Soln:(a) medians

A median is defined as the line segment joining the vertex to the mid â€“ point of the opposite side of a triangle.

**5.A triangle whose no two sides are equal is called**

Soln:(b) A scalene triangle

A Scalene triangle is defined as the triangle in which no sides are equal.

**6.A triangle whose two sides are equal is known as**

Soln:(b) An isosceles triangle

An isosceles triangle is a triangle that has two equal sides.

**7.A triangle whose two sides are equal is called**

Soln:(a) An equilateral triangle is defined as a triangle whose all sides are equal.

**8.The sum of the lengths of side of a triangle is known as its**

Soln:(c) Perimeter

Perimeter is defined as the sum of the length of all the sides of a triangle

**9.A triangle having all sides of different length is known as its**

Soln:(a) Scalene triangle.

A Scalene triangle is defined as a triangle having all sides of different length.

**10.A triangle whose one angle is more than 90 ^{o }is called**

Soln:(d) An obtuse triangle.

An obtuse triangle is a triangle whose one angle is more than 90^{o}