This is the concept of algebra, we are required to find the value of the variable a, given that M lies between L and N. LM=8a=56 Therefore solving the above we get: 8a=56 dividing both sides by 8 we get: (8a)/8=56/8 a=7 Given that MN=7a Then; MN=7*7=49 Thus LN=56+49=105 Thus; a=7 and LN=105