I think the answer is 78 because more usually mean addition so 57+21=78
You would set it up: .5/100 = x/490 and then cross multiply .5 time 490 and 100 times x, and end up with: 245=100x. divide by 100, and get 2.45
When a polygon is regular, that means that all of its sides are the same length and all of its angles are the same. A heptagon has seven sides and you know that all of them measure 3 inches. You can find the perimeter by adding all of the side measures together, so 3 + 3 + 3 + 3 + 3 + 3 + 3, or 3 x 7. So, the perimeter of the heptagon is 21 inches.
Number 6 the y intercept is 50 because that’s the point where it crosses the y axis and 7 I believe it would be D= 200