Question

Intr-un dreptunghi ABCD, AB=40mm, BC=30mm, AE_|_ BD, E apartine lu BD si EF_|_ BC, F apartine lui BC. aflati:
a) lungimea diagonalei BD.
b) aria patrulaterului ABFE

Answer 1

a) In triunghiul ABD: AD=30mm ,AB=40 mm =>[tex]BD^{2} = 30^{2} + 40^{2} [/tex]
$BD^{2} =900+1600$
$BD= \sqrt{2500} =50mm$
b) A ABFE(trapez dreptunghic deoarece mB=90,mF=90,EF=AB/2)=(AB+EF)*EM(inaltime,EM perpendiculara pe AB)/2=60*30/2=900$mm^{2}$