Răspuns:
Explicație pas cu pas:
aria=ac ori bd/2= 20 ori 40/2=20 ori 20=400 cm²
ac∩ bc={o}
oc=ac/2=>oc=20/2=>oc=10 cm
od=bd/2=>od=40/2=>od=20 cm
in Δdoc:
od²+oc²=cd²
20²+10²=cd²
400+100=cd²
500=cd²=>cd=√500=>cd=10√5 cm
perimetrul= 4ori cd= 4 ori 10√5=40√5 cm
