Question : Three circles of radius 6 cm each touch each other externally. Then the distance of the centre of one circle from the line joining the centres of the other two circles is equal to:
Option 1: $6\sqrt{5}\;\mathrm{cm}$
Option 2: $6\sqrt{3}\;\mathrm{cm}$
Option 3: $6\sqrt{2}\;\mathrm{cm}$
Option 4: $6\sqrt{7}\;\mathrm{cm}$
Latest: SSC CGL 2024 final Result Out | SSC CGL preparation tips to crack the exam
Don't Miss: SSC CGL Tier 1 Scorecard 2024 Released | SSC CGL complete guide
Suggested: Month-wise Current Affairs | Upcoming Government Exams
Correct Answer: $6\sqrt{3}\;\mathrm{cm}$
Solution :
Let the three circles form an equilateral triangle $\triangle \mathrm{ABC}$ with each side equal to the diameter of a circle, which is $12\;\mathrm{cm}$. $\mathrm{BC = BD + DC = 6 + 6 }=12\;\mathrm{cm}$ The altitude $(h)$ of an equilateral $\triangle \mathrm{ABC}$, $h = \frac{\sqrt{3} a}{2}$ where $a$ is the length of a side of the triangle. $h = \frac{12\sqrt{3}}{2} = 6\sqrt{3}$ Hence, the correct answer is $ 6\sqrt{3}\;\mathrm{cm}$.
Candidates can download this ebook to know all about SSC CGL.
Admit Card | Eligibility | Application | Selection Process | Preparation Tips | Result | Answer Key
Question : Two circles touch each other externally. The radius of the first circle with centre O is 12 cm. Radius of the second circle with centre A is 8 cm. Find the length of their common tangent BC.
Option 1: $6 \sqrt{6} \mathrm{~cm}$
Option 2: $8 \sqrt{3} \mathrm{~cm}$
Option 3: $8 \sqrt{2} \mathrm{~cm}$
Option 4: $8 \sqrt{6} \mathrm{~cm}$
Question : Two circles touch each other externally. The radius of the first circle with centre O is 6 cm. The radius of the second circle with centre P is 3 cm. Find the length of their common tangent AB.
Option 1: $3\sqrt{2}$ cm
Option 2: $4\sqrt{2}$ cm
Option 3: $6\sqrt{3}$ cm
Option 4: $6\sqrt{2}$ cm
Question : Two circles of the same radius 6 cm, intersect each other at P and Q. If PQ = 10 cm, then what is the distance between the centres of the two circles?
Option 1: $10\mathrm{~cm}$
Option 2: $8\mathrm{~cm}$
Option 3: $6\sqrt{11} \mathrm{~cm}$
Option 4: $2\sqrt{11} \mathrm{~cm}$
Question : There are two circles which touch each other externally. The radius of the first circle with centre O is 17 cm and the radius of the second circle with centre A is 7 cm. BC is a direct common tangent to these two circles, where B and C are points on the circles with centres O and A, respectively. The length of BC is:
Option 1: $2 \sqrt{118} $ cm
Option 2: $2 \sqrt{119} $ cm
Option 3: $2 \sqrt{113} $ cm
Option 4: $2 \sqrt{117}$ cm
Question : Two circles of radius 10 cm and 5 cm touch each other externally at point A. PQ is the direct common tangent of those two circles of centres O1 and O2, respectively. The length of PQ is equal to:
Option 1: $10\sqrt{2}$ cm
Option 2: $8\sqrt{2}$ cm
Option 3: $9\sqrt{2}$ cm
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile