Răspuns:
3.∆ABC(<A=90°)AB=12cm;BC=20cm
T.P. AC=√20²-12²=√400-144=√256=16cm
sinB=AC/BC =16/20=4/5
cosB=AB/BC =12/20=3/5
tgC=AB/AC=12/16=3/4
ctgC=AC/AB=16/12=4/3
4..∆ABC(<A=90°)AC=20cm;AB=15cm
T.P. BC=√20²+15²=25cm
sinB=AC/BC=20/25=4/5
cosB=AB/BC=15/25=3/5
tgC=AB/AC=15/20=3/4
ctgC=AC/AB=20/15=4/3
5..∆ABC(<A=90°)AB=2√3cm;sinC=2/3=AB/BC
BC=3AB/2=3×2√3/2=3√3cm
T.P. AC=√BC²-AB²=√27-12=√15
sinB=AC/BC=√15/3√3=3√5
cosB=AB/BC=2√3/3√3=2/3
tgC=AB/AC=2√3/√15=2√5/5
ctgC=AC/AB=√15/2√3=√5/2
6..∆ABC(<A=90°)
