Roland needs a length of thread to complete an exercise. He has a 12cm long thread but his teacher says he needs an additional three-quarters of what he has. What is the total length required? Let's be accurate as possible.
An additional three - quarters of 12cm is needed which is 12cm * (3 / 4) = 9cm. The total length required is 12cm + 9cm = 21cm.
The answer: 21.