1. The following statement

1 The volume of a cone is one third of that of a cylinder; Wrong. Bottom and height are not specified.

A rectangle has 12 sides and 8 vertices; Wrong, you should say cuboid.

The radius of the circle has been expanded by five times, and the circumference has also been expanded by five times; Yes, the radius or diameter is proportional to the circumference.

Of all the line segments connecting a point outside the straight line with points on the straight line, the vertical line segment is the shortest. That's right.

There are (b) correct ones.

A 1 B 2 C 3 D 4

In the following figures, d is not necessarily an axisymmetric figure.

A circle (with countless symmetry axes) B rectangle (two)

C isosceles triangle (one) D right triangle (not necessarily, only when isosceles right angles exist)

The sum of three integers is 60, and their least common multiple is 273, so the product of these two integers is (b).

a 273 B 8 19 C 19 1 1D 3549

Description: 273=3*7* 13, 60=3* 13+3*7.

application problem

A man pours water from a cup full of water into another empty jar. If you pour two glasses of water, the jar weighs 0.6 kg. If you pour 5 glasses of water, the can weighs 0.975 kg. How many kg does this empty can have?

Solution: The difference between 5 cups and 2 cups is 3 cups, and the weight difference is 0.975-0.6=0.375 kg.

Weight of each cup: 0.375/3=0. 125 kg.

Empty tank weight: 0.6-2 * 0.125 = 0.35kg.

The original theater had 28 rows of seats with 34 people in each row. After the expansion, 4 rows will be added, which will accommodate 296 more people than before. How many people will sit in each row after the expansion?

Solution: There were 28*34=952 people. After the expansion, they can sit: 952+296= 1248 people.

After expansion, each row: 1248/(28+4)=39 people.

There are two cuboid containers, container A is empty, measured from the inside, the bottom is 40 cm long and the width is 30 cm; Container B contains water, measured from the inside, the bottom is 30 cm long, 20 cm wide and the water depth is 24 cm; Pour part of the water in container B into container A, so that the water depths of the two containers are the same. How many centimeters is the water depth?

Solution. The volume of water is: 30*20*24= 14400 cubic centimeters.

As high as the water depth, that is, 14400 ÷ (40 * 30+30 * 20) = 8cm.