diagonala imparte patratul in doua triunghiuri dreptunghice,in oricare dintre ele teorema lui Pitagora este
d^{2} =l^{2} +l^{2} =2l^{2}
a) d^{2} =2x5^{2} =2x25=50
d=\sqrt{50} =5\sqrt{2} cm
b) d^{2} =2x169=338
d=\sqrt{338} =13\sqrt{2} cm
c) d^{2} =2x576=1152
d=\sqrt{1152} =24\sqrt{2} cm
d) d^{2} =2x81=162
d=\sqrt{162} =9\sqrt{2} cm
e) d=4\sqrt{2} cm
f) d=2\sqrt{2} mm
g)d=10\sqrt{2}
h) d^{2} =2x\sqrt{2}^{2} =2x2=4
d=\sqrt{4} =2dam
i) d^{2} =2x(1/3)^{2} =2x(1/9)=2/9
d=\sqrt{2/9} =\sqrt{2} /3 dm
j) d=\sqrt{2} cm