\[\frac{2}{5} \cdot 340 = \frac{2 \cdot 340}{5} = \frac{680}{5} = 136\]
Ответ: 136 dm²
4 dm² 2 cm² = 4 ⋅ 100 cm² + 2 cm² = 400 cm² + 2 cm² = 402 cm²
\[\frac{1}{3} \cdot 402 = \frac{402}{3} = 134\]
Ответ: 134 cm²
\[\frac{3}{7} \cdot 1260 = \frac{3 \cdot 1260}{7} = \frac{3780}{7} = 540\]
Ответ: 540 cm²
3 m² 16 dm² = 3 ⋅ 100 dm² + 16 dm² = 300 dm² + 16 dm² = 316 dm²
\[\frac{3}{4} \cdot 316 = \frac{3 \cdot 316}{4} = \frac{948}{4} = 237\]
Ответ: 237 dm²
\[\frac{4}{9} \cdot 531 = \frac{4 \cdot 531}{9} = \frac{2124}{9} = 236\]
Ответ: 236 m²
8 cm² 4 mm² = 8 ⋅ 100 mm² + 4 mm² = 800 mm² + 4 mm² = 804 mm²
\[\frac{1}{6} \cdot 804 = \frac{804}{6} = 134\]
Ответ: 134 mm²