There are two circles with centers A and B having radii 5 cm and 3 cm.

Question

GMATBusters’ Quant Quiz Question -3

For past quiz questions, click  here

There are two circles with centers A and B having radii 5 cm and 3 cm. They touch each other internally. If the perpendicular bisector of segment AB meets the bigger circle at P and Q. Find the length of PQ.

A. 2√3
B. 3√4
C. 4√6
D. 5√6
E. 5√7

A. 2√3
B. 3√4
C. 4√6
D. 5√6
E. 5√7

Raxit85 · Answer

If, as per figure, PDA is right angle triangle, then
PD^2 + DA^2 = AP^2
PD^2 =25-1=24 
PD= 2root6.
PQ = 2*PD = 4root6

Imo. C

ashwini2k6jha · Answer

ANSWER:C
LET BOTH CIRCLE TOUCH INTERNALLY AT POINT T .
And let R be the point at which PQ bisect AB
AB=AT-BT-5-3=2
AR=2/1=1
Length of PQ=2PR=2X sqrt PA^2 - AR^2
PQ=2 X Sqrt 25-1=2 sqrt 24=4 sqrt 6
=2 X Sqrt

uc26 · Answer

Let O be the point on AB that bisects AB. AP and AQ would be the radius of the larger circle which is 5.
AB is the difference between the radius of the larger circle and the smaller circle which is 5-3= 2
Thus we have two right triangles with hypotenuse as 5 and one leg as 1.
Thus OP^2= OQ^2= 5^2- 1^2
OP= OQ= square root of 24
Thus, PQ= 2* square root of 24
PQ= 4√6

Answer: C

Archit3110 · Answer

given are two circles with centers A and B having radii 5 cm and 3 cm touching internally 
The perpendicular bisector of segment AB meets the bigger circle at P and Q. Target Find the length of PQ.
Let the point of touch of two circles be C ; so AC = 5cm and BC = 3cm
also a LINE PQ which for circle center A pass through the line AC and intersect it at point D
we get AC-BC = AB ; 5-3 ; 2 cm
and PQ is perpendicular bisector so AD = 1 cm
now for ∆ PAD ; PA = 5cm and AD = 1 cm we can determine PD ; i.e 25-1 ; 24 ; 2√6
and since PQ is a chord of circle so its distance will be 2 *PD ; 2*2√6 ; 4√6
OPTION C

There are two circles with centers A and B having radii 5 cm and 3 cm. They touch each other internally. If the perpendicular bisector of segment AB meets the bigger circle at P and Q. Find the length of PQ.

A. 2√3
B. 3√4
C. 4√6
D. 5√6
E. 5√7

A. 2√3
B. 3√4
C. 4√6
D. 5√6
E. 5√7

SohGMAT2020 · Answer

There are two circles with centers A and B having radii 5 cm and 3 cm. They touch each other internally. If the perpendicular bisector of segment AB meets the bigger circle at P and Q. Find the length of PQ.

A. 2√3
B. 3√4
C. 4√6
D. 5√6
E. 5√7

Solution:

Attachment:

Picture2.png [ 8.23 KiB | Viewed 2907 times ]

OAP is a right-angled triangle, in which, OA = 1 and AP = 5,

Therefore, \(OP^2 = AP^2 - AO^2 = 25 - 1 ; OP = \sqrt{24} = 2\sqrt{6}\)
PQ = 2 OP = \(4\sqrt{6}\)

So, C is the correct answer

ArunSharma12 · Answer

length of AB = 2cm

perpendicular bisector of AB divides AB in two equal parts at point O.
in one of triangles formed by perpendicular bisector,
AP^2 = AO^2 + OP^2
OP^2 = 25 - 1 = 24; OP = 2√6

similarly, in other triangle, OQ also = 2√6

PQ = OP + OQ = 4√6
Ans: C

yashikaaggarwal · Answer

Let line segment AB and PQ cut each other at M
Let AM = X, BM = Y, PM = QM = Z
In triangle APM,
AP^2 = AM^2+PM^2 
5^2 = X^2+Z^2 
25-X^2 = Z^2 -------(1)

BP^2 = BM^2+PM^2 
3^2 = Y^2+Z^2 
9-Y^2 = Z^2 -------(2)

25-X^2 = 9-Y^2 
16 = X^2-Y^2 --------(3)

A. 2√3 = 2Z => Z = √3
Putting value of Z in equation 1&2 respectively
25-3 = 22 = X^2 & 
9-3 = 6 = Y^2.
Again putting value of X^2 & Y^2 in equation 3
22-6 = 16 => 16 = 16 (matching)

B. 3√4 = 2Z => Z = 3
Putting value of Z in equation 1&2 respectively
25-9 = 16 = X^2 & 
9-9 = 0 = (zero value, which cannot be null)

C. 4√6 = 2Z => Z = 2√6
Putting value of Z in equation 1&2 respectively
25-12 = 13 = X^2 & 
9-12 = (negative value, which cannot be negative)

D. 5√6 = 2Z => Z = 5√6/2
Putting value of Z in equation 1&2 respectively
25-75 = (negative value, which cannot be negative)

E. 5√7 = 2Z => Z = 5√7/2
Putting value of Z in equation 1&2 respectively
25-87.5 = (negative value, which cannot be negative)

IMO A

Posted from my mobile device

tejas29d · Answer

OA is 4root6 . again pythagoras theorem is to be used

Kinshook · Answer

Given:
1. There are two circles with centers A and B having radii 5 cm and 3 cm.
2. They touch each other internally.
3. The perpendicular bisector of segment AB meets the bigger circle at P and Q.

Asked: Find the length of PQ.

Attachment:

Screenshot 2020-06-07 at 1.06.04 PM.png [ 30.75 KiB | Viewed 2812 times ]

AB = 5 - 3 = 2
\(AT = TB = \frac{AB}{2} = 1\)

\(In \triangle PTB\)

\(\angle PTB = 90^0\)
TB = 1
PB = radius of bigger circle = 5
\(PT = \sqrt{PB^2 - TB^2} = \sqrt{5^2 - 1^2} = \sqrt{24} = 2\sqrt{6}\)

\(PQ = PT*2 = 4\sqrt{6}\)

IMO C

HoneyLemon · Answer

c, IMO

AB = 2 . So PQ/2 = root (24). so PQ = 2 root(24) = 2 * 2 (root (6)) = 4 root(6).
So c .

Posted from Mobile device

coreyander · Answer

Let the meeting point of two circles be Y.

AY=AB+BY.......... (AY=Radii of the bigger circle 5 cm. BY=Radii of the smaller circle 3cm) 
 	herefore AB = 5-3 = 2cm.

A perpendicular bisector of segment AB will divide AB & itself into two equal parts...(AX=XB, PX=XQ) Let the perpendicular bisector meet AB at X.
 	herefore AX=XB=1cm

In \ triangle APX , AP = Radii of bigger circle 5cm, AX=1cm.
By Pythagoras theorem,  PX=2\sqrt 6

PQ = PX+XQ
PQ = 2PX

PQ= 4 \sqrt 6 
Thus, PQ is (C)  4 \sqrt6

There are two circles with centers A and B having radii 5 cm and 3 cm.

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

There are two circles with centers A and B having radii 5 cm and 3 cm.

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards