9.
如图所示,△ABC中,已知BC=16,高AD=10,动点Q由C点沿CB向B移动(不与点B重合).设CQ长为x,△ACQ的面积为S,则S与x之间的函数关系式为( )
| A. | S=80-5x | B. | S=5x | C. | S=10x | D. | S=5x+80 |
5.
如图,在△ABC中,∠ABC=90°,BD为AC的中线,过点C作CE⊥BD于点E,过点A作BD的平行线,交CE的延长线于点F,在AF的延长线上截取FG=BD,连接BG、DF.若CF=6,AC=AF+2,则四边形BDFG的周长为( )
| A. | 9.5 | B. | 10 | C. | 12.5 | D. | 20 |
2.
如图,矩形ABCD的对角线AC,BD交于点O,∠AOB=60°,AB=4,则矩形ABCD的面积为( )
0 295222 295230 295236 295240 295246 295248 295252 295258 295260 295266 295272 295276 295278 295282 295288 295290 295296 295300 295302 295306 295308 295312 295314 295316 295317 295318 295320 295321 295322 295324 295326 295330 295332 295336 295338 295342 295348 295350 295356 295360 295362 295366 295372 295378 295380 295386 295390 295392 295398 295402 295408 295416 366461
| A. | 16$\sqrt{3}$ | B. | 32 | C. | 8$\sqrt{3}$ | D. | 32$\sqrt{3}$ |