Can someone me find the area of this circle and round to the nearest tenth

Suppose investors can earn a return of 2% per 6 months on a treasury note with 6 months remaining until maturity. the face value of the t-bill is $10,000. what price would you expect a 6-month maturity treasury bill to sell for? (round your answer to 2 decimal places. omit the "$" sign in your response.)

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.