Question

Two equal sides of an isosceles triangle with fixed base ‘a’ are decreasing at the rate of 9cm/sec.
How fast is the area of the triangle decreasing when two sides are equal to ‘a’?

Answer 1

Step-by-step explanation:

Pythagoras Theorem and Differentiation Helps

Step-by-step explanation:

In the isosceles triangle, if base is b, let us think x as the similar sides.

which means,Base BC is b and both equal sides AB,AC are x

We know that on x being equal to base (b), the side of triangle decreases.

i.e.

So, is x equals b,then area is decreasing, but how fast?

i.e. when x =b.

For Finding Area,

Draw a perpendicular AD to BC  

i.e. AD⊥BC

In Isosceles triangle,

perpendicular from vertex to the side bisects the side

i.e. D is the mid point of BC