1. **State the problem:** We need to find the volume of water in the trough when the water depth is three quarters of the height of the trough. 2. **Given dimensions:** Length = 1.5 m, Width = 0.7 m, Height = 0.8 m. 3. **Convert dimensions to centimetres:** Since 1 m = 100 cm, - Length = $1.5 \times 100 = 150$ cm - Width = $0.7 \times 100 = 70$ cm - Height = $0.8 \times 100 = 80$ cm 4. **Calculate the depth of the water:** Water depth = $\frac{3}{4} \times 80 = 60$ cm 5. **Formula for volume of a cuboid:** $$\text{Volume} = \text{length} \times \text{width} \times \text{height}$$ 6. **Calculate the volume of water:** $$\text{Volume of water} = 150 \times 70 \times 60 = 630000 \text{ cm}^3$$ 7. **Interpretation:** The volume of water in the trough is $630000$ cubic centimetres.