b)
Average of first 12 numbers arranged in ascending order is 24.5. Avg. of first 9 numbers is 25.2 and that of last 9 is 24.3. The numbers from 4th to 9th are increasing by one. find 4th and 9th no.
c)
in a circle of radius 34cm, two chords of length 60cm and 32cm are parallel to each other and on the oppposite side of the centre of the circle then find the distance betweenthe chords.
please help. thanks?
2015-12-07 5:15 pm
回答 (2)
2015-12-07 6:22 pm
✔ 最佳答案
12 * 24.5 - 9 * 25.2 = 67.2so we know that numbers 10, 11, 12 add up to 67.2
let x = 4th number
4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 = 9 * 24.3
x + x + 1 + x + 2 + x + 3 + x + 4 + x + 5 + 67.2 = 218.7
6x + 82.2 = 218.7
6x = 136.5
x = 22.75
4th = 22.75
9th = 27.75
distance is 46 units between the chords
2015-12-07 5:16 pm
DO YOUR OWN HOMEWORK.
收錄日期: 2021-05-01 20:38:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20151207091544AAmeSoO