what do you observe about the form of the equation of any circle whose center is at the point of origin​

Abus travels 36 miles in 45 minutes. enter the number of miles the bus travels in 60 minutes at this rate.

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

Asurvey of 2,000 doctors showed that an average of 3 out of 5 doctors use brand x aspirin.how many doctors use brand x aspirin