Which describes a plan that ABC median Ad is also an altitude

Alright, lets get started.

Two sides of the rectange are 14 and s.

So, the area of the rectange would be =

So, the area of the rectange would be =

A triangle is cut from the rectangle.

The height of the triangle is =

The base of the triangle is = 14

So area of the triangle would be =

area of the triangle would be =

area of the triangle would be =

So, the area of shaded region = area of rectange - area of triangle

the area of shaded region =

As per given in question, area of shaded region is 84, hence

equation

So, this is the equation for s : Answer

Hope it will help :)