Tolong pakai cara yaa

7. L = 1/2 x 12 x 15 x sin 60°
= 1/2 x 12 x 15 x 1/2√3
= 45√3

8. AC^2 = AB^2 + BC^2 - 2.AB.BC.cos B
AC^2 = 10^2 + 12^2 - 2.10.12.cos 60°
AC^2 = 100+144-2.10.12.1/2
AC^2 = 244 - 120
AC^2 = 124
AC = √124
AC = √ 4 x 31 = 2√31

^ dibaca kuadrat

9.sin @ = depan/miring= 2/3
sisi samping = √3^2 -2^2 = √9-4=√5

tan @ = depan/samping= 2/√5 x √5/√5 = 2/5 √5

10.
=cos^2@(1+sin@) -cos^2@(1-sin@)/(1-sin@)(1+sin@)
= cos^2@+cos^2@.sin@ - cos^2@+cos^2@.sin@/1-sin@+sin@-sin^2@
=2 cos^2@.sin@/1-sin^2@
=2 cos^@.sin@/cos^2@ (cos^@ dicoret krn sama atas bawah)
= 2 sin @

7. luas ABC = 1/2 12 15 x sin60
= 90 x 1/2√3
= 45√3

8. AC² = 10²+ 12² - 2 10 12 cos 60
= 100 + 144 - 10 12
= 244 - 120
= 124
AC = √124 = 2√31

9. sin alpa = 2/3 pake rumus phytagoras sehingga nanti alasnya bernilai √5.
dit tan alpa = de/sa = 2/√5 = 2/5√5

10. gak tau akuuu