挑战习题
1/5单选题
难度:

1.太阳光线与地面成60°的角,照射在地面上的一只皮球上,皮球在地面上的投影长是,则皮球的直径是(  )
A 5
B 15
C 10
D 8
提示1:
5qC55o2u6aKY5oSP5bu656uL55u06KeS5LiJ6KeS5b2iRENF77yM54S25ZCO5qC55o2u4oigQ0VEPTYwwrDvvIxERT0xMDxpbWcgd2lkdGg9MjAgaGVpZ2h0PTE4IHNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvOTEvQjQvckJBQ0psV2Jtb1hodUs5U0FBQUJwaGR3SHBZMzk4LnBuZyIgPuWPr+axguWHuuetlOahiA==
正确答案:Qg==
6Kej77ya55Sx6aKY5oSP5b6X77yaREM9MlLvvIxERT0xMDxpbWcgd2lkdGg9MjAgaGVpZ2h0PTE4IHNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvOTEvRDIvckJBQ0oxV2Jtb1hoRThETkFBQUJuTnRpLS1ZNDI2LnBuZyIgPu+8jOKIoENFRD02MMKw77yMPGJyPuKItOWPr+W+l++8mkRDPURFc2luNjDCsD0xNe+8jjxicj7mlYXpgIlC77yOPGJyPjxpbWcgd2lkdGg9MTU1IGhlaWdodD0xMTggc3JjPSJodHRwczovL3AyLnFpbmdndW8uY29tL0cxL00wMC85MS9CNC9yQkFDSmxXYm1vWHlDZUtlQUFBWWtVekN2QkU1MTYucG5nIiA+