Hey there!
Formula: πr^2
r = radius
pi = 3.1415926535898 (but we can say it approximately equals 3.14)
Your equation (3.14)(4.2)^2 = answer
4.2^2 = 4.2 × 4.2 = 17.64
New equation: 17.64 × 3.14 = 55.3896
We round our answer to the nearest tenth
Answer: 55.4 ☑️
Good luck on your assignment and enjoy your day!
~LoveYourselfFirst:)