Below is an instruction that describes a task. Write a response that appropriately completes the request in Swahili. Please answer in Swahili.

### Instruction:
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?

### Response:
 Inahitajika theluthi tatu zaidi ya sentimita 12 ambayo ni 12cm*(3/4) = <<12*(3/4)=9>>9cm
Urefu jumla unaohitajika ni 12cm+9cm = <<12+9=21>>21cm