no 5, tolong yaa yang tau caranya...

cari tinggi segitiga dahulu
L ∆ = √s(s-13)(s-15)(s-8)
s = keliling/2 = (15+13+8)/2 = 18
L ∆ = √18(18-13)(18-15)(18-8)
= √18(5)(3)(10)
= √2700
= 30√3
L ∆ = a × t / 2
30√3 = 15 × t / 2
t = 30√3 × 2 / 15
t = 4√3
sin Q = t/QR
= 4√3/13
= (4/13)√3