2. In the figure, PQRS is a parallelogram and
ZQPR = 90°, QP = 9 cm, QR = 15 cm and
PT I QR. Find (a) area of A QPR (b) area of
parallelogram PQRS.
Answers
Answer:
(a) Since, AQPR is a right angled triangle because Z QPR = 90°
and, Hypotenuse = QR = 15cm (given)
height = PR = ? =
base = QP = 9cm (given)
So, By Pythagoras theorem,
(Hypotenuse )2 = ( Base )2 + ( height
=> (QR)2 = (PR)2 + (QP)2
=> (15)? = (PR)? + (9)²
Now, take (9)2 to other side as it is positive, so taking it other side, it will become negative.
=> (15)2 - (9)2 = (PR)2
using the identity, a? - b² = (a+b)(a-b)=> (15 + 9)(15 9) = (PR)?
=> 24 x 6 = (PR)?
=> 144 = (PR)?
=> PR = 144
=> PR = V12 × 12
=> PR = 12 cm = height.
thus, area of APQR,
x base x height
=} x 12 x 9
when we divide 12 by 2 we get 6, i.e. 12 ÷ 2 = 6
= 6 x 9
54cm? (ANSWER)
(b) Since, PQRS is a parallelogram,so, opposite sides are equal,
.. QR = PS = 15cm
and,
PQ = RS = 9cm
so, area of AQPR = area of APRS (equation 1)
hence, area of PQRS,
= area of AQPR + area of APRS
= area of AQPR + area of AQPR (from equation 1)
= 2 x area of AQPR
= 2 x 54 cm
= 108cm2
Answer:
hope it helps u
Step-by-step explanation:
Since, ∆QPR is a right angled triangle because QPR = 90°
and, Hypotenuse = QR = 15cm (given)
height = PR = ?
base = QP = 9cm (given)
So, By Pythagoras theorem,
( Hypotenuse )² = ( Base )² + ( height )²
=> (QR)² = (PR)² + (QP)²
=> (15)² = (PR)² + (9)²
Now, take (9)² to other side as it is positive, so taking it other side , it will become negative.
=> (15)² - (9)² = (PR)²
using the identity, a² - b² = (a + b)(a - b) :-
=> (15 + 9)(15 - 9) = (PR)²
=> 24 × 6 = (PR)²
=> 144 = (PR)²
=> PR =
=> PR =
=> PR = 12 cm = height.
thus, area of ∆PQR,
= × base × height
= × × 9
when we divide 12 by 2 we get 6 , i.e. 12 ÷ 2 = 6
= 6 × 9
= 54cm² (ANSWER)
(b) Since, PQRS is a parallelogram,
so, opposite sides are equal ,
QR = PS = 15cm
and,
PQ = RS = 9cm
so, area of ∆QPR = area of ∆PRS ----(equation 1)
hence, area of PQRS,
= area of ∆QPR + area of ∆PRS
= area of ∆QPR + area of ∆QPR (from equation 1)
= 2 × area of ∆QPR
= 2 × 54 cm²
= 108cm² (Answer)