7.ipotenuza 10, cateta mica 10/2=5, cateta mare (Pitagora) 5√3
arie 5*5√3/2=25√3/2 unitati patrate
8.BC=6/cos15°
cos15°=cos(45°-30°)=cos45°cos30°+sin45°sin30°=(1/√2)* (√3+1)/2
BC=6*2√2/(√3+1)=12√2(√3-1)/(3-1)=6√2(√3-1)6,2116...≈6,212
9 fie xsi y lungimile catetelor
atunci x+y=17
xy=2*30=60
z²-17z+60=0
rezolvand cu Δ obtinem x=12 unitati lungime y=5unitati lungime ,(si x=5, y=12) numere pitagorice
