Il faut utiliser pythagore.
RS^2=TS^2+RT^2
Donc TS^2=RS^2-RT^2
RT^2=x^2+VT^2
Donc VT^2=RT^2-x^2
TS^2=VS^2+VT^2=(RS-x)^2+VT^2
Donc VT^2=TS^2-(RS-x)^2
Donc RT^2-x^2=TS^2-(RS-x)^2
RT^2-x^2=RS^2-RT^2-(RS^2-2RSx+x^2)
2RT^2-x^2=RS^2-RS^2+2RSx-x^2
2RT^2=2RSx
x=RT^2/RS
x=8*8/10=64/10=6,4cm.
