Question

急！！！！！！！请学霸帮忙

Answer 1

 

Answer 2

3.14X(25÷2)2一3.14X(20÷2)2
=3.14X12.5X12.5一3.14X100
=3.14X156.25一314
=176.125

Answer 3

200除以2=10 0 100x100x13.14

Answer 4

[(25÷2)²-(20÷2)²]×3.14×¼

Answer 5

3.14×（12.5×12.5-10×10）÷4

Answer 6

圆环面积的4分之1