Cần gấp ạ. ai biết giải giúp với ạ

Two sides of a triangle mesure 20cm and 30cm. what is the measure of the third side

1c) the number 131 is a term in the sequence defined by the explicit rule f(n)=5n-4. which term in the sequence is 131? 2a) write the first four terms of the function f(n)=n^2-1 2b) what is the 10th term of the sequence defined by the explicit rule f(n)=n^2-1 2c) the number 224 is a term in the sequence defined by the explicit rule f(n)=n^2-1. which term in the sequence is 224?

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15