The opening of a bird’s nest is in the form of a circle. The opening has a diameter of 18 centimeters. What is the area of the opening?

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is

4+(2+x) can you me solve this problem

Acircle has a circumference of 7.850 units. what is its radius?