24.如圖,在△ABC中,∠B=90°,AB=6cm,BC=12cm,動(dòng)點(diǎn)P從點(diǎn)A開始沿著邊AB向點(diǎn)B以1cm/s的速度移動(dòng),動(dòng)點(diǎn)Q從點(diǎn)B開始沿著邊BC向點(diǎn)C以2cm/s的速度移動(dòng).若P、Q兩點(diǎn)同時(shí)開始運(yùn)動(dòng),當(dāng)點(diǎn)P運(yùn)動(dòng)到點(diǎn)B時(shí)停止,點(diǎn)Q也隨之停止.設(shè)運(yùn)動(dòng)時(shí)間為t(s).
(1)當(dāng)移動(dòng)幾秒時(shí),△BPQ的面積為9cm
2?
(2)當(dāng)移動(dòng)幾秒時(shí),以B、P、Q為頂點(diǎn)的三角形與△ABC相似?