Tak kak diagonal` delit pryamougol`nik na 2 ravnyh pryamougol`nyh treugol`nika,to eto zadanie reshaem po teoreme Pifagora:
diagonal` AC=gipotenuza
AB=3cm
AD=4cm
AC(v kvadrate)=AB(v kvadrate)+AD(v kvadrate)
AC(v kvadrate)=9+16=25
AC=5
otvet:diagonal` raven 5 sm
