Aylana va doira

3.6.7 Doiraning yuzi.
1. Yuzasi 9π bo’lgan doira aylanasining uzunligini hisoblang.
A) 32 π B) 3π C) 6π D) 43 π E) 2π
2. Doiraning radiusi 40% ga oshsa, uning yuzi necha foizga oshadi?
A) 140 B) 196 C) 96 D) 4 E) to’g’ri javob berilmagan
3. Doiraning yuzi 96% ortishi uchun uning radiusini necha foizga orttirish kerak?
A) 40 B) 62 C) 4 D) 196 E) 140
4. Har birining diametri 50 ga teng bo’lgan uchta quvur suv o’tkazish qobiliyati shu uchta quvurnikiga teng bo’lgan bitta quvur bilan almashtirildi. Yangi quvurning diametrini toping.
A) 85 B) 150 C) 50√3 D) 75 E) 100
5. Yuzasi 6, 25π bo’lgan doira aylanasining uzunligini hisoblang.
A) 5π B) 2, 25π C) 2, 5π D) 5, 25π E) 5, 5π
6. Diametri 50 ga teng ikkita vodoprovod quvurini, suv o’tkazish qobiliyati shu ikki quvurnikiga teng bo’lgan bitta quvur bilan almashtirildi. Katta quvurning diametrini toping.
A) 50√2 B) 100 C) 50√3 D) 70 E) 75
7. Ikkita doiraning umumiy vatari 600 va 1200 li yoylarni tortib turadi. Kichik doira yuzining katta doira yuziga nisbatini toping.
A) 1 : 2 B) 1 : 3 C) 1 : 4 D) 2 : 3 E) 2 : 5
8. Doiraning radiusi 20% ga kamaytirilsa, uning yuzi necha foizga kamayadi?
A) 25 B) 36 C) 45 D) 40 E) 20
3.6.8 Doira sektori va segmentining yuzi.
1.Markazi O nuqtada bo’lgan aylana AB yoyining uzunligi 6 ga teng. Agar aylananing radiusi 4 ga teng bo’lsa, OAB sektorning yuzini
toping.
A) 12 B) 8 C) 10 D) 14 E) 16
2.Uzunligi m ga teng bo’lgan vatar 900 li yoyga tiraladi. Hosil bo’lgan segmentning yuzini hisoblang.
A) πm 8 2 B) m 82 (π − 2) C) (π−√ 43)m2 D) πm 4 2 E) m 42 (π − √2)
3. Doiraning radiusi r ga teng. 900 li yoyga mos keladigan segmentning yuzini toping.
A) πr 82 B) r2 2 (π − 2) C) πr 42 D) r8 2 (π − 2) E) r4 2 (π − 2)
4.Radiusi R ga teng bo’lgan doiraning markazidan bir tomonda ikkita bir-biriga parallel vatar o’tkazildi. Bu vatarlardan biri 1200 liyoyni tortib turadi. Parallel vatarlar orasida joylashgan kesimning yuzini toping.
A) πR 6 2 B) πR 4 2 C) πR 3 2 D) 3πR 8 2 E) πR 8 2
5. Radiusi 6 ga teng bo’lgan doira va markaziy burchagi 900 bo’lgan doiraviy sektorlar tengdosh. Sektorning perimetrini toping.
A) 2π + 10 B) 6(π + 4) C) 3(π + 8) D) 4π + 15 E) 6(π + 3)
6. To’g’ri chiziq doiraning aylanasini uzunliklarining nisbati 1 : 3 kabi bo’lgan ikki yoyga ajratadi. Bu chiziq doiraning yuzini qanday nisbatda bo’ladi?
A) 2 π π+1 +1 B) 1:9 C) 3 π π+2 +2 D) 4:9 E) 3 π π− +2 2
7.Doira sektorining yuzi 72π ga teng. Agar sektorning yoyi 450 ga teng bo’lsa, shu doira aylanasi uzunligini toping.
A) 46π B) 40π C) 42π D) 48π E) 44π
8.Radiusi √13 ga, yoyining radian o’lchovi 2 ga teng bo’lgan sektorning yuzini hisoblang.
A) 13 B) 26 C) 39 D) 52 E) 18