if it's true simple interest then each year's interest is the same so interest for one year is a quarter of 241.50 which give you the rate but if each year's interest in left in the account the result will be different , it is a really poorly worded question
First you use Pythagorean theorem to find LO is square root of 194(13^2 + 5^2)=13.9. Then use the same method to find OM (194+13^2=363, square root of 363 is 19.1) and get that OM is 19.1