Solution:
Let be the radius, be the height and be the slant
height of a cone of semi-vertical angle 45°. Then,
and
Let
Let be the lateral surface. Then,
Also, at we have
The semi-vertical angle of a cone is 45°. If the height of the cone is 20.025, then its approximate lateral surface area, is
Let be the radius, be the height and be the slant
height of a cone of semi-vertical angle 45°. Then,
and
Let
Let be the lateral surface. Then,
Also, at we have