cat 2020 Question 21

Question

Let C1 and C2 be concentric circles such that the diameter of C1 is 2cm longer than that of C2. If a chord of C1 has length 6 cm and is a tangent to C2, then the diameter, in cm of C1 is

Accepted Answer

Now we know that the perpendicular from the centre to a chord bisects the chord. Hence at the point of intersection of tangent, the chord will be divided into two parts of 3 cm each. As you can clearly see in the diagram, a right angled triangle is formed there.

Hence $(r+1)^2=r^2+9$ or $r^2$ + 1 + 2r = $r^2$ + 9 or 2r = 8 or r = 4cm

Hence the radius of the larger circle is 5cm and diameter is 10cm.

Hence $(r+1)^2=r^2+9$ or $r^2$ + 1 + 2r = $r^2$ + 9 or 2r = 8 or r = 4cm

Hence the radius of the larger circle is 5cm and diameter is 10cm.

Question 21.

No video explanation yet — we're on it and uploading soon!

Question 21.

Question Explanation

No video explanation yet — we're on it and uploading soon!