Narrative proof.

the altitude drawn from the vertex of an isosceles triangle bisects the base.

Yes altitude from vertex bisects the base of isosceles triangle because it form congruent triangle.

Step-by-step explanation:

Already we know the two adjacent side of isosceles triangle are equal. Also an altitude is perpendicular to the base thus form right angle in both the smaller triangle. As altitude is also common to both the triangle thus by side-angle-side congruent test they are congruent.

Now, angles opposite to equal sides are equal thus take tan of it. Which is altitude/half of base.

  Thus both are same.

40 minutes

step-by-step explanation:

add the time and multiply by 2