Practicing Success
Two circles of radius 15 cm and 37 cm intersect each other at the points A and B. If the length of common chord is 24 cm, what is the distance (in cm) between the centres of the circles? |
44 45 42 40 |
44 |
AB = 24 cm = AM = MB = 12 cm In triangle AMO \( { OM}^{2 } \) = \( {AO }^{ 2} \) - \( {AM }^{ 2} \) = \( { OM}^{2 } \) = \( {37 }^{ 2} \) - \( {12 }^{ 2} \) = \( { OM}^{2 } \) = 1369 - 144 = \( { OM}^{2 } \) = 1225 = OM = 35 cm In triangle AMO' \( { O'M}^{2 } \) = \( {AO' }^{ 2} \) - \( {AM }^{ 2} \) =\( { O'M}^{2 } \) = \( {15 }^{ 2} \) - \( {12 }^{ 2} \) = \( { O'M}^{2 } \) =225 - 144 = \( { O'M}^{2 } \) = 81 = O'M = 9 cm Now O'O = OM + O'M = (35 + 9) = 44 cm Therefore, the distance between the center of the circles is 44 cm. |