What are the main features of the ocean floor

In the image, point a marks the center of the circle. which two lengths must form a ratio of 1 : 2? (options are in the images since thought they were harmful phrases)

Acollection of coins has value of 64 cents. there are two more nickels than dimes and three times as many pennies as dimes in this collection. how many of each kind of coin are in the collection?

Use multiples to write two fractions equivalent to 7/9. 14/18, 8/10 6/8, 21/27 10/12, 28/36 14/18, 21/27