2(b)
PQ : ST = 5.6 : 2.8 = 2:1

Since PQR~SRQ,
PQ : ST = QR : SR
2:1 = 3.6:SR
SR = 1.8 cm

2(c)
Prism 2's planar surface area = 300 / 15 = 20 cm²
Since Prism 1 ~ Prism 2,
15:6 = 20:Prism 1's planar surface area
Prism 1's planar surface area = 8 cm²
Prism 1's volume = 8*6 = 48 cm³

4(a)
AC = 2*25 = 50km

4(b)
AB = 60km
Let a = AC, b = AB, ∠A = C
BC = √(b² + a² - 2ab*cos(C))
=√((60)² + (50)² - 2(50)(60)*cos(100°))
=√(6100 - 6000cos100°)
= 84.5097 km

4(c)
Let a = AC, b = AB, c = BC
∠B = cos⁻¹((c²+b²-a²)/2cb)
= cos⁻¹((84.5097²+60²-50²)/(284.509760))
= cos⁻¹(0.8127)
= 0.622 rad
= 0.622*180/π
= 35.638°

compass bearing:
90° - (35.638° - (180°-90°-65°))
=90° - 10.638°
=S79.362°E

Hope it helps!

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