# Typography of Geometry Problem 1375: Isosceles Triangle, Interior Cevian, Exradius,
Excircle, Altitude to the Base, iPad Apps

### Proposition

In the figure below,
ABC is an isosceles triangle (AB = BC) with altitude BE = h. D is a point on
AC, r_{1} is the exradius of the triangle ABD corresponding to AD and r_{2} is the exradius of
the triangle DBC corresponding to BC. Prove that r_{2} - r_{1}
= h.

*BD is called an interior
cevian of triangle ABC.*

* *

See solution below

See also:

Original problem 1375.

### Geometric Art using iPad or Mobile Apps

Geometric art is a form of art based on the use and application of geometric figures. A geometric figure is any set or combination of points, lines, surfaces and solids.

A mobile app or mobile application software is a computer program designed to run on smartphones and tablet computers.