Which of the following is not the properties of triangle
Exterior angle of a triangle is equal to sum of two opposite interior angles.
Sum of any two sides of a triangle is greater than third side.
None of the sides are equal in scalene triangle.
Sum of three angles of a triangle is equal to two right angles.
Answers
Step-by-step explanation:
Objective:
This topic gives an overview of;
Exterior Angle of a Triangle and Its Property
Angle sum property of a Triangle
Two Special Triangles: Equilateral and Isosceles
Sum of the Lengths of Two Sides of a Triangle
Right-Angled Triangles and Pythagoras Property
Properties Of Triangles
Exterior Angle of a Triangle and Its Property
Draw a triangle ABC and produce one of its sides, say BC as shown in . Observe the angle ACD formed at the point C. This angle lies in the exterior of ∆ABC. We call it an exterior angle of the ∆ABC formed at vertex C. Clearly ∠BCA is an adjacent angle to ∠ACD. The remaining two angles of the triangle namely ∠A and ∠B are called the two interior opposite angles or the two remote interior angles of ∠ACD. Now cut out (or make trace copies of) ∠A and ∠B and place them adjacent to each other.
An exterior angle of a triangle is equal to the sum of its interior opposite angles.
Consider ∆ABC. ∠ACD is an exterior angle.
To Show: m∠ACD = m∠A + m∠B
Through C draw CE, parallel to BA
Justification
Steps Reasons
a) ∠1 = ∠x BA || CE and AC is a transversal. Therefore, alternate angles should be equal.
b) ∠2 = ∠y BA || CE and BD is a transversal.
c) ∠1 + ∠2 = ∠x + ∠y
d) Now, ∠x + ∠y = m ∠ACD.
Hence, ∠1 + ∠2 = ∠ACD From the figure above.