Question : Two circles touch each other externally. The radius of the first circle with centre A is 18 cm. The radius of the second circle with centre B is 8 cm. Find the length of their common tangent CD.
Option 1: 23 cm
Option 2: 26 cm
Option 3: 24 cm
Option 4: 25 cm
Correct Answer: 24 cm
Solution : Given: The radius of the first circle, $r_1$ = 18 cm The radius of the second circle, $r_2$ = 8 cm We know that, Length of the direct common tangent $=2 \sqrt{r_1 \times r_2}$ $=2 \sqrt{18 \times 8}$ $=2 \sqrt{144}$ $=2 \times 12$ $= 24$ Hence, the correct answer is 24 cm.
Result | Eligibility | Application | Selection Process | Cutoff | Admit Card | Preparation Tips
Question : Two circles with radii of 25 cm and 9 cm touch each other externally. The length of the direct common tangent is:
Question : Two circles with their centres at O and P and radii 8 cm and 4 cm respectively touch each other externally. The length of their common tangent is:
Question : If the radius of two circles is 6 cm and 9 cm and the length of the transverse common tangent is 20 cm, then find the distance between the two centres.
Question : Two circles of radii 8 cm and 3 cm, respectively, are 13 cm apart. AB is a direct common tangent touch to both the circles at A and B respectively then the length of AB is:
Question : Out of two concentric circles, the radius of the outer circle is 6 cm and the chord PQ of the length 10 cm is a tangent to the inner circle. Find the radius (in cm) of the inner circle.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile