If the (linear) scale factor of two similar solids is k, then
(a) all corresponding length properties of the two solids have scale factor k.
(b) all corresponding area properties of the two solids have scale factor k2.
(c) all corresponding volume properties of the two solids have scale factor k3.
Let k be the (linear) scale factor of similar cones ABC and ADE.
Then
We are given that the corresponding surface areas have scale factor 2.
Therefore by (b) above, the scale factor of the surface areas is
k2 = 2. Therefore,
and
Taking reciprocals of both sides,
which is approximately 0.707,
So to cut the cloth of the tent in half, you would cut it straight
across from B to C, which is about 70.7% of its height from the top.
Edwin