Question

Is altitude of a isosceles triangle a perpedicular to its base

Answer 1

Yes the altitude of a isosceles triangle is perpendicular to its base

Answer 2

yes it is.

since the isosceles triangle has two sides equal and the altitude drawn meets the third side at its midpoint.

we get two triangles, on comparison we get both triangles congruent, with the following conditions.

two sides if isosceles triangle are equal.

third side bisected by the altitude.

altitude is common to both the triangles.

by SSS condition.

so the angle subtended by the altitude on the third side is equal.

also the sum of these angles form a linear pair.

so the angles are 90 degree each.

therefore the altitude is PERPENDICULAR.