Final answer:
Statements (a), (c), and (d) are true while (b) and (e) are false. The sum of three angles of a triangle is always 180 degrees, an equilateral triangle has all its sides equal in length, and one angle of a right angled triangle is 90 degrees. A triangle cannot have two sides greater than 90 degrees, and a triangle with three different side lengths is called scalene, not isosceles.
Step-by-step explanation:
Let's address each of these statements one at a time: (a) The sum of three angles of a triangle is always 180 degrees. This statement is true. No matter what the size or shape of the triangle, the sum of its internal angles will always equal 180 degrees. (b) A triangle can have two of its sides greater than 90 degree. This statement is false. A triangle cannot have two angles greater than 90 degrees as the sum would exceed 180 degrees. (c) An equilateral triangle has all of its three sides equal in length. This statement is true. By definition, an equilateral triangle has three sides of equal length. (d) One angle of a right angled triangle is always equal to 90 degrees. This statement is true. The defining characteristic of a right triangle is one 90-degree angle. (e) A triangle whose all three sides are different in length is called an isosceles triangle. This statement is false. A triangle with all sides of different lengths is called a scalene triangle, not an isosceles triangle.
Learn more about Properties of Triangles