THIS is a story about a boy called Sparky. For Sparky, school was all but impossible. He failed every subject in the eighth grade. He got a zero in physics. It made him the worst physics student in the school's history. He didn't do much better in sports. He made the school golf team, but lost the only important match of the season.
      He didn't have friends, either. Other kids didn't care about him. If a classmate said “hello” to Sparky outside of school, he would feel very surprised. There's no way to tell how he might have done at dating(约会). Sparky never once asked a girl to go out in high school. He was too afraid of being turned down.  
     He was a loser(失败者), and he and his classmates knew it. But, somehow, he decided to keep trying. The only thing important in his life was drawing. He was proud of his ability even though no one else appreciated it. He submitted(递交) some cartoons for his high school yearbook, but they were rejected.
     After completing high school he wrote a letter to the Walt Disney Studios. He was told to submit some samples. He spent a great deal of time on the drawings. They were rejected. Another loss for the loser.  
     So Sparky decided to write his own auto biography(自传) in cartoons. He created his childhood self – a little-boy loser: Charlie. He never succeeded in kicking a football and never got a date with the little red-haired girl. Sparky, the boy who had such a lack of success in school and whose work was rejected again and again, was Charles Schulz. He created the Peanuts comic strip and the world-famous cartoon characters Charlie Brown and Snoopy.

如图所示，把底面直径为60mm米，高为200mm的圆柱形钢材，锻压成底面为正方形，高为157mm的长方体零件毛坯，那么零件毛坯的底面正方形的边长为（　　） （π取3.14）

如图所示，把底面直径为60mm米，高为200mm的圆柱形钢材，锻压成底面为正方形，高为157mm的长方体零件毛坯，那么零件毛坯的底面正方形的边长为（　　） （π取3.14）