Respuesta :

find the length of AB
AB²=20²+15²
AB²=400+225
AB²=625
AB=25

then find AD and BD
20²=AD·25
400=AD·25
AD=16
15²=BD·25
225=BD·25
BD=9
now use the geometric mean theorem (name?) to find CD
CD=√(9·16)
CD=√144
CD=12 cm

ACCESS MORE