S = S 1ADM ADB3S = S 1BCQ BCD33

95.

S = S 1

ADM

ADB

3

BCQ

BCD

S + S = (S 1 + S )

ADM

BCQ

ADB

CBD

= S 1

ABCD

S = S .

Suy ra:

_DMBQ

2

_ABCD

Nhưng

S

_MDP

= S

_MPQ

_và

S

_QMN

= S

_QNB

.

Suy ra :

S = S + S = S + S = S 1

MNPQ

MNQ

MPQ

MDP

QNB

ABCD

S

MNQP

= 300 : 3 = 100 (cm )

²

.