1 √× √

2 94.2÷3. 14=30 cm 30? ×6=5400 square centimeters

Three (4÷2)? × 3.14× 2+(4× 3.14 )× (5× 2) =150.72 square decimeter.

Ⅳ1× 3.14×1.5× 20 = 94.2 square meters.

5 2.4 ÷ 12 = 0.2m 0.2？ ×6=0.24 square meters

p77

A piece of 5.6 0.8 1500 3050

Two, 1? × 3. 14×3÷3 =3. 14 cm2

3 0.8×0.8× 1.5=0.96 m2.

4 94.2 ÷ 3.14 ÷ 2 =15cm15 square× 3.14 = 706.5cm.

(2) 706.5×6.28÷ 1000≈44 liters

Five 100.48 present (2? ×3. 14)=8 cm

p78

I. Volume 1200 Surface area 700

Volume 1000 surface area 600

Volume 602.88 surface area 40 1.92

Ii 1 17.68

The third (1) area 32. 185 needs 643.7 yuan.

(2) 15.7 tons

p79

One. Surface area 45.7 184 volume 19.7438+092.

Two. 2637.6 kg

Three. About 9 cm

Four. No, because you need the bucket of 1 1.

Give me some, my hands are sore! ! ~