What is the radius if the diameter is 21 inches

10.5

Step-by-step explanation:

Radius is the diameter/2: 21/2 = 10.5

126

Step-by-step explanation:

From the statement , we have been given given

blue jays : black crows : red robins : cardinal

That is :

59 : 68 : 12 : 1

Total ratio = 59 + 68 + 12 + 1 = 140

Therefore : the number of blue jays if 300 visit is :

ratio of blue jay / total ratio x 300

That is

59/140 x 300

= 126. 4285714

≈ 126