Find the perimeter of a regular nonagon with a side length of 21? 126 147 168 189

Estimate the product. round the first factor to the nearest whole number, round the second factor to the nearest ten, and then multiply. 3 8/9 × 96

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Eis the midpoint of line segment ac and bd also line segment ed is congruent to ec prove that line segment ae is congruent to line segment be