题目

如图，在正方形网格图中建立一直角坐标系，一条圆弧经过网格点A、B、C，请在网格图中进行下列操作： （1） 利用网格确定该圆弧所在圆的圆心D点的位置，并写出点D坐标为▲； （2） 连接AD、CD，则⊙D的半径为（结果保留根号），∠ADC的度数为； （3） 若扇形DAC是一个圆锥的侧面展开图，则该圆锥底面半径为．（结果保留根号）． 阅读理解 　　CBC is a famous air company which has over twenty planes carrying passengers and goods, flying along 12 fixed lines all over the world．Its service is very good but some passengers are still not satisfied with it and that is why in 2003 and 2004 the company received letters of complaints from consumers or passengers who pointed out over a dozen kinds of problems which are divided in groups in the following table．Those about passengers’ things carried by the plane are Baggage problems．Customer service refers to service work with passengers are not satisfied with．Oversales of seats are about the fact that more seats are sold and as a result the plane is too crowded to be safe．Refund problems appear when passengers fail to receive the money paid back to them because of what they have lost．Fares are problems about the price of tickets． 　　Consumer Complaints Received By the CBC (1) About how many complaints about Credit were received by the CBC in 2003? [　　] A． 28 B． 29 C． 30 D． 31 (2) By about what percent did the total number of complaints decrease from 2003 to 2004? [　　] A． 40% B． 60% C． 75% D． 100% (3) If the circle graphs below show total consumer complaints for 2003, which graph shows a dark part that is about Flight problems and Refund problems together? [　　] A． B． C． D． (4) Which of the following statements can be inferred from the table? a．In 2003 and in 2004, complaints about Flight problem, Baggage, and Customer service together took about 50 percent of all consumer complaints received by the CBC Company． b．The number of Special passengers complaints was unchanged from 2003 to 2004． c．From 2003 to 2004 the number of Flight problem complaints increased by more than 2 percent． [　　] A． only a B． only b C． a and b D． a and c (5) From the passage we can know that ________． [　　] A． customers are not satisfied with CBC B． sometimes CBC sells more tickets than its plane’s fixed seats C． CBC has more than twenty planes which fly to all the capital cities of the world D． customers can only buy tickets with ready money