Question

Do as directed:
1.Prove that the bisector of the vertical angle of an isosceles triangle is perpendicular to the base.
2.Construct a triangle ABC in which BC= 6 cm ; ԼB = 40˚ ; ԼC = 110˚
3. Evaluate 25.75 + 2.09 – 13.6
4. Simplify and express the result as a rational number in its lowest form:
3.125 + 0.125 + 0.50 – 0.225
5. A horse is tied to a pole with a 21 cm long string . Find the area that can be grazed by the horse.

Answer 1

Answer:

Prove that the bisector of the vertical angle of an isosceles triangle is perpendicular to the base.

Let in triangle ABC,AD is bisector of vertical angle.

In ∆ABD and ∆ACD

AB=BC

angle BAD=angle CAD

AD is common line.

By SAS congruency ∆ABD congruent to ∆CBD

So,

angle ADB=angle ADC

let angle ADB=x.

so angle ADC=x.

x+x=180

2x=180

x=90

Hence it's proved.