<human>:  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?
<bot>: How many centimeters are needed? ** An additional three-quarters of 12cm is needed which is 12cm*(3/4) = <<12*(3/4)=9>>9cm
How many centimeters are needed? ** The total length required is 12cm+9cm = <<12+9=21>>21cm
#### 21