22.如圖1,點(diǎn)A、B、C是數(shù)軸上從左到右排列的三個(gè)點(diǎn),分別對(duì)應(yīng)的數(shù)為-5、b、4.某同學(xué)將刻度尺如圖2放置,使刻度尺上的數(shù)字0對(duì)齊數(shù)軸上的點(diǎn)A,發(fā)現(xiàn)點(diǎn)B對(duì)應(yīng)刻度1.8cm,點(diǎn)C對(duì)齊刻度5.4cm.
(1)在圖1的數(shù)軸上,AC=
個(gè)長(zhǎng)度單位;在圖2中,AC=
cm;數(shù)軸上的一個(gè)單位長(zhǎng)度對(duì)應(yīng)刻度尺上的
cm;
(2)求在數(shù)軸上點(diǎn)B所對(duì)應(yīng)的數(shù)b;
(3)若點(diǎn)Q是數(shù)軸上一點(diǎn),且滿足AQ=2AB,通過計(jì)算,求點(diǎn)Q所表示的數(shù)