Heya im angel! im new here can someone help me with this thanks :)

Afarm that has 4 x 10^2 acres has 1.2 x 10^5 cattle. what is the average number of cattle per acre? write the answer in scientific notation. answere asap

The pyramid below was dissected by a horizontal plane which shape describes the pyramid horizontal cross section

Arectangle has a width of 5 cm and a length of 10 cm. if the width is increased by 3, how does the perimeter change?