T H E
E L E M E N T S 
Book VI
Proposition 8

Therefore
as BD which subtends the angle BAD in the triangle ABD is to DA which subtends the angle at C in the triangle ADC equal to the angle BAD,
so is AD itself which subtends the angle at B in the triangle ABD to DC whcih subtends the angle DAC in the triangle ADC equal to the angle at B,
and
so also is BA to AC, these sides subtending the right angles; [VI.4]
therefore
the triangle ABD is similar to the triangle ADC. [VI.Def.1]


Previous Page
Return to Propositions
Next Page
