Question

ex 30,31! va rog! Ajutați.ma!

Answer 1

30)
cos 60°=1/2
AB/BC=1/2
12/BC=1/2
BC=2×12=24
sin 60°=√3/2
AC/BC=√3/2
AC/24=√3/2
AC=24√3/2=12√3
A=12×12√3/2=72√3 cm²
P=12+12√3+24=36+12√3=12(3+√3) cm


31)
tg C=3/4
AB/AC=3/4
20/AC=3/4
AC=20×4/3=80/3=26,(6)
BC=√[20²+(80/3)²]=√(400+6400/9)=√(3600+6400)/9=100/3=33,(6)
P=20+80/3+100/3=20+180/3=20+60=80 cm
A=(20×80/3)/2=1600/6=800/3=266,(6) cm²