How does the modern study of history challenge earlier historians

 It is an analytical field of study that uses constantly changing information and reassessments to form new theories on past events.

Explanation:

Modern history uses all available data, including new archaeological projects, primary and secondary sources, and other contemporary historians to reassess earlier histories and come up with new postulations based on this evidence. Sometimes these assertions attempt to validate previous arguments, while other times they directly challenge the conclusions made by previous generations of historians.

the answers are 1 and 4

254.34

step-by-step explanation:

the formula for area of a circle is given by

a = pi * r^2

a = pi * 9^2

a = 81*pi

using 3.14 as an approximation for pi

a = 3.14*81

a = 254.34