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21 APR 1970

係華三乽張 第 6六十 月三年戌庚藩夏 WAH KIU YAT Po 日橋

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僑榮

70英文中學會考試題預習專欄

數學科

文書院主編

(廿五)

(b) ABCD is a quadrilateral in which A = __ B = 90°

j

AB 6 BC100AD18". Prove that BD hissote

SOLUTION

ADC.

A

const.

19770英文中學會考試題預習專欄

堅道英文書院主編

(a) Draw AD LBC

in ABD / ADB = 90°

3- 45°

BAD 180°

(90° + 45°)

45° (/ sum of A)

BD AT siden opp. L

By Pythagora#,

AD

Hence, area of AABC = 3(AD)(30)

Important Theoreme

MATHEMATICS (25)

Aran theeraus on-triangle:

1. A - † (bane z height)

2. Beren's Formulas Azna

1 * † (a+bro)

u on the name Bars (or aqual bages) and

between the same parallels are equal in area,

- rasi theorems on quadrilateral

1. Area of reot. – Length x breadth"

2. área of square. » square on ene sideā

3. Aron of // gran a base x height

4.

(180. 2008. and (50) as the Base batt

(or equal bases) and between the sano parallel are equal in area.

åres of trapezium - Average of two barsa z

6. área of rhombus

Pythagoras 'theodezy

height

médian x height.

of the product or two diagonala

In a rì.A, the area of the square on hypotenuse equals the sum of areas of aquazen, on two adjacRAS sides.

Az pla 1: Find the area of a triangle whose sides

are. (p2 - 42)

inches

SOLUTION: Let a,

o be the sides of the A

Jush that a

200

1.8. the A is right-angled

bo = 1(281)(p2-

pu (p2 - g2)

HOTE: THẢO Hwables can also be solved by using the

erga termula,

where ca

-2. (a+b+c)

* P *Fq • \p{p+q)

(P-Q) STO.

Bennelo Zc AÐ in an altitude of AABOT P, Q are

points on AD produced such that DP:

RA DO MAG. Prove that 34 - Cr

PROOF IS AB> 1G, then from the fig. as showr

ADP BDC.

ABD, BDQ, PDC, GEA Are

By Pythagoras thegroni From 21.▲ 804 : BD BA From rt.A BQD: BQ" -

Q2 = BD2 +

(1).

2 D

CDA: CD2 A

GP2 - CD2 + DP2

(2)

(1) & (2) DP AB & AC = Dal

CP

BQ

adding the case

From It. XADO AD

DO

By Pythagoras

+ √22) (6)

►10.6 (uq.in)

(35) + (6-2)2

60-60√

18.57

√18.57 4.31 (in.)

(b) LA - LB - 90° //BC

"Take a point I on AD. such that XD

TD BO

XBCD is a //gram.

Prom 15, ▲ ABX、

IX-18- 10

By Pythagoras, BX"

x = 10

BD

diag.

Hence, in //gam XECD, BX - BC 10 (in.)

XBCD is a Thombus

BD bisects ADC

Exemple 5: As enown,

RS // AB

Prove that

(a) ASPA+ ASPQ - ASPD (b) APR AASQ AABD (o)APKR KSCQ- ABKD

PROOF (a) Join KD, PR

(b) Join KA

100

and PQ //AD

ASPD. AKPD+AKPS + AKSD

As on the same base and between the Saame // are equal in area / KPD

ДЕРЕ - ДАРЕ - ДАРЕ

AXSD- AKSQ

APS la in common

.

▲KPD + AKSD + AKFS - AAPS + AkSQ

AKPS

ASPA+ ASPQ - ASFD

ASQ - AKSA Z\XSQ + \\QKA

AKSA-AESP - † of //gram K3BP

ARSQ = 1 of //gran KSCQ- Aoki - AQKR - 4 of //gran QDRK AASQ + APR

♣ of (KBBP + XSCQ + QIRK + AFKR )

of ABCD

(0) Join KC

the proof is then).

Example 31 As shown in figure, ABP is a st. line and

Mais the mid-point of AP., Frove that KK bisects the area of

PROGF) Join PK

PMK, AMK are on

ABC

Дарс - Двок + Дрск + Аск ABDC-of // gram ABOD Дрок Драк + Деск

• 1 of (DQKR + QCSK) ACBK - ACSK + ASBK

or (CSKQ + SBPX)

英文科

(廿五)

meaning HER (B) moaning-lear man

nean man (D) man of means (1) moann man

snoo said that she would come

wouldn't she, (B) won'4 {(0) did she didn't sho

15. He dares na to fight,^.

10. Let

daren't ha (B) dosan's dare doesn't" ka

isn't he

go before it is dark,

(A) will you (B) won't you (C) shall wa {D} aren't wa

17. Let me gojenia?

(A) will you (B) wouldn't you (0) aren't YOL (D) don't you

18. You dare not go,

(A) dare you (R) don't you (C) do you

D) are you

19. As wenal, she

har father.

(A) dara not

look at the stern face.

(D) hopes no dares not (0) will not

20. He returned home

long distance.

can hardly

breathing heavily. He

(A) ran (B) should have run (C) was running (D) had run (B) must have run

21. Not even

when he found the house on rize,

(A) he felt a bit sorry (3) ■ bit sorry, he felt (C) Terry did he feel (D) he did feel sorry a bi (B) did he feel a bit sorry

Ko has never seen Joan again, arran

so were his mother (B) so and not his mot neither had his mother (D) nor had his mother either had his mother

21. I can never understand him and he can nevez

understand me ....

A】 tos (3) nino, (C) as well (D) neither

the door, he remembered leaving the key in the house. (A) Having looked (3) Looked (C) Looking. (D) Being lanked: (B) To look

.... he had been sick, he would have won. (A) If not that (B) Unless (C) But for (D) Bub that: (1) Anyway

26. Refrigerators now .... a very important part in

our daily life.

(A) take (3) do (c)

((( (D) play (F) have-

27. You ... every book in my library.

(A) welcome (B) are welcomed

(C) will be welcomed (D) welcome v

(B) are welcome to

28. I am quite sorry ........ your unbrella for no many

months.

(4) (3) having used to: (C) for borrowing

to have borrowed (1) borrewing

The musiuens vont pappened last night MAR the carelessness of the driver.

oving to (B) osused to (0) dus to ((7) for the sake of (B) forsed by An accident happened here last nighw CarGLOBURGOm of the driver, so

ewing to (3) caused to (C) dus to for the sake of (E) formed by

Coses him, name. Defore sinse you two came out from the same university an

(A) sught to know (B) should koar

(C) would have heard - (D) ought to have heard.

must hear.

32. I get used to English food but I can never

accustomed to.... late.

go to bed (B) #leep (0) have slept

(5) ** ** 100). (E) *leeping

43. Kovaz .......... punotual and this makes us very

with her.

Oak she... (3) she 'oan (C) will she` be dinho, (3) is her

14. I akauld have worked much harder, in that conse:2.

(A) have not failed (3) should not fall

(C) should not have failed

8

must not have failed (E) could not have railek

the shot, he threw himself down innodiatel Haring heard ( (B)By hearing

After begring (D) On hearing (X) For hearing

equal bases (PM

KA)

and of the same altitude.

ARMP AKMA

Since AKMP - AKMB + AKEP

KBP,

KBC are on the same base (KB) and between the same // (BK//PC)

ДКВР - ДКВС

Hence, KMP AIIB + AKBC KHBC

AKMP - AKA proved

AKBIA KHEC

K bisects the area of AABC.

Example 4

(a) In AB, 4B = 5" EC

Calculelo the area of AEC and length of AC

± of ABCD - ABDK + 1【DQKR + QOSK) SBPX)

or ABCD = 2,ⱭBDK + DQKR + 2.QCSK + SBPK

ABCD = (DQKR + QCSE + SBPE) + APKR APKR 2.BDK +QCSK

APKR

QCSK

BDK

Example 63 ABCD is a parallelogram, any line parallel

to BA cuts BC, AG, AD at X, Y,, 2 resp. Prove that AAXY - ADYZ.

uiveni ABCD in a //gram

XIZ // AP

To prove: AAXY - ADYZ

Proofs Join CZ

In A CAZ, CXA

They are on the same base (CX) and between

Of which, ACXY is common to both

By subtraction,

In As ZD. ZIC

ACZY

They are on the same base (ZY) and between the same parallels (DC // ZX)

CZY - / DYZ

DOZY - DAXY and Aczy - ADYZ

AAKY - ADIZ

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日六十月三年戌庚歷夏 WAH KIU YAT PO

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