A circle with an arc AB measuring 90 degrees

Use a graphing calculator to solve the equation - 3 cos t = 1 in the interval from 0 ≤ theta ≤ 2 π round to the nearest hundredth.

The difference(s) between the grand canyon and valles marineris is/are: (a) the grand canyon was formed by water, but valles marineris was not. (a) valles marineris is much longer than the grand canyon. (c) valles marineris is much wider than the grand canyon. (d) valles marineris has large volcanoes near it. all of the above

What first caused people to consider that the continents were once one large landmass?