What is 24 / 2 × 12

What is 24 / 2 × 12

one hundred and forty-four

How many minutes is 12 hours, how many seconds is 30 minutes, how many hours is 240 minutes, how many minutes is 300 seconds,

12 hours equals 720 minutes, 30 minutes equals 1800 seconds, 240 minutes equals 4 hours
300 seconds is five minutes

The radius of the cone bottom is 1, the height is twice the root sign 2, and the cross-sectional area of the axis is PAB. Take a rope from point a and chase the side to point a to find the shortest rope length
Please write down the detailed steps and draw the image

OB = r = 1 & nbsp;, & nbsp; & nbsp; PO = 2 times root sign 2
&As shown in the figure: in RT △ POB, by Pythagorean theorem: Pb & amp; sup2; = Po & amp; sup2; + ob & amp; sup2; = (double root 2) & amp; sup2; + 1 & amp; sup2; = 9
                    ∴ PB=3  ,
&Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; in the fan graph, R = P & # 39; a & # 39; = 3
&Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; length of arc ABA & 39 = perimeter of cone bottom = 2 π r = 2 π * 1 = 2 π
&According to the formula of arc length of fan: l = (2 π RN) / 360 degree
                                             ∴2π=(2π*3n)/360°
&The & nbsp; & nbsp; & nbsp & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & & nbsp; & nbsp; & nbsp; & amp & nbsp; & nbsp; & & nbsp; & & nbsp; & & nbsp; & & nbsp; & & nbsp; & & nbsp; & & nbsp; & nbsp; & amp & nbsp; & nbsp; & nbsp; & nbsp; & amp & nbsp; & amp & nbsp; & nbsp & nbsp; & & nbsp; & & nbsp; & & nbsp; & & amp & nbsp; & amp & amp & amp & amp & nbsp; & & nbsp; & & nbsp; & & nbsp; & & nbsp & amp & amp & amp & nbsp; & & nbsp; & & amp & amp & nbsp; & & amp & amp & nbsp; & & amp & amp & amp & nbsp; & amp & amp & amp & nbsp & amp & nbsp; & & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & amp & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; that is, ∠ AP & # 39; a & # 39; = 120 degree
&Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; according to the line between the two points is the shortest, connecting AA & # 39;, & nbsp; then the shortest rope length = AA & # 39;
&& nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;
&& nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;, then ∠ D & # 39; P & # 39; a & # 39; = 60 degree
&Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; in RT △ P & # 39; D & # 39; a & # 39; = 30 degree
&The & nbsp; & nbsp; & nbsp & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & & nbsp; & nbsp; & nbsp; & & nbsp; & nbsp; & nbsp; & & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & (?) 39; = 3 / 2 (root 3)
&Nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp;; AA & # 39; = triple root 3 & nbsp; & nbsp;, & nbsp; & nbsp; & nbsp; PD = P & # 39; D & # 39; = 3 / 2
&Therefore, the shortest rope length must pass through the midpoint D of the bus bar Pb of the cone. At this time, the shortest rope length is 3 times the root sign 3

(put the serial number of the correct answer in brackets)
(1) Numbers that are both combined and odd are ()
A.2.5 B.51 C.7 D.29
(2) A composite number has () factors
A. 1 B.2 C.3 D. at least 3

1.d 2.d

The perimeter ratio of the big and small circles is 5:3. The area difference between them is 48 square centimeters. How many square centimeters are the areas of the two circles?

If the perimeter ratio is 5:3, the radius ratio is 5:3, so the area ratio is 25:9
Big circle = 48 ÷ (25-9) / 25 = 75 square centimeter
Small circle = 75-48 = 27 square centimeters

The formula of base area of hexagonal prism?

The bottom is a regular hexagon with a side length of A
S=（3√3/2）a²

Known arc length 17.7m, radius 7.5m, find chord length and chord height

Given arc length C = 17.7m, radius r = 7.5m, the center angle of chord length L and chord height h? Arc is a. a = C / r = 17.7 / 7.5 = 2.36 radians = 2.36 * 180 / pi = 135.218 degrees, l = 2 * r * sin (A / 2) = 2 * 7.5 * sin (135.218 / 2) = 13.869h = R-R * cos (A / 2) = 7.5-7.5 * cos (135.218 / 2) = 4.643

What is the sum of: - 1,2, - 4,8, - 16,32 ··· 512?

（-1+2）+（-4+8）+…… +（-256+512）
=1+4+16+64+256
=341
PS: children have to do their own homework in the future, do you know --

What is the meaning of Guazhou poem?

From Jingkou to Guazhou is only a river, and from Jingkou to Nanjing is only a few mountains. The spring breeze blows green on both sides of the Yangtze River. When will the moon shine on me?

Given that the ellipse X & # 178; / (10-K) + Y & # 178; / (K-2) = 1, the focus is on the y-axis, if the focal length is equal to 4, then the real number K=

2c=4,c=2
a^2=k-2,b^2=10-k,
c^2=a^2-b^2=k-2-(10-k)
=2k-12=4
k=8.