The distance between the two toes of the compass is 4 cm.
The three internal angles and degrees of this triangle are 140, 40 and 40 respectively.
1.∫3.5-meter-long rope wraps around the trunk five times, leaving 0.36 meters.
The circumference of trunk is (3.5-0.36) ÷ 5 = 0.628m..
The radius of trunk is 0.1m.
∴ The area of the trunk section is πr? =3. 14×0. 1? =0.03 14m？
A: The cross-sectional area of the trunk is 0.03 14 square meter.
2.200×6000×3×0.5%= 18000 yuan
A: The insurance premium payable by the school is18,000 yuan.
3. Set this book to ***x pages.
1/3x+(x- 1/3x)×3/5+(x- 1/3x)×3/5- 10 = x
x=75
This book has 75 pages.
4. Let the speed of car A be x, then the speed of car B is 3/2x.
x×0.6+3/2x×0.6= 120
x=80
A: The speed of car A is 80 kilometers per hour.
Suppose Xiaoming reads a book and has read X pages, then he hasn't read 5x pages.
Then look at it after 30 pages.
(x+30)/(5x-30)=3:5
x=24
So I have read 24 pages, but I haven't read 120.
So this book ***24+ 120= 144 pages.
A: This book *** 144 pages.