中二MATHS ２題。。。 [複製鏈接]

有２條數希望大家幫手計下－　－＂



打錯左野。。AE=AD 才對－　－

禁入去睇會好Ｄ

1. In. Prove the figure, AD//BC,AE//AD??? and p+q = 180. Prove that AB is // to EC

Angle p = angle ADE (base angles, isosceles triangle)

angle ADE = angle BCD (corresponding angles, AD//BC)

therefore, angle p =angle BCD

since, p+q=180 (given)

therfore, AB is // to EC (interior angle supplementary)

2. (a) let PR be x and PQ be 3x

x^2+9x^2 = 36^2 (Pythagorus theorem)
      10x^2  = 1296
          ..................
   PR=  x  = 11.384 (cor. to 3 d.p.)
    PQ = 3x = 34.153 (cor. to 3 d.p.)

2(b) Area of PQR

(11.384x34.153)/2
= 194.4 cm square (cor. to 1 d.p.)

引用第1樓bon1於2009-01-01 11:40發表的  :
1. In. Prove the figure, AD//BC,AE//AD??? and p+q = 180. Prove that AB is // to EC
Angle p = angle ADE (base angles, isosceles triangle)
angle ADE = angle BCD (corresponding angles, AD//BC)
.......

點解係x^2+9x^2=36^2(Pyth.thm.)
我唔係好明點解係9x..
因為你之前係ＬＥＴ　x=PQ  3x=PR　的。。

引用第2樓ivanabcdefg於2009-01-01 12:09發表的  :
點解係x^2+9x^2=36^2(Pyth.thm.)
我唔係好明點解係9x..
因為你之前係ＬＥＴ　x=PQ  3x=PR　的。。

3x all square

哦。。
原來如此。。
真係唔該曬你～