What theorem can be used to prove that the two triangles are similar?

For one history test, keith had to answer 40 questions. of these 40 questions, keith answered 28 of them correctly. what percent did keith get on his history test? round your answer to the nearest tenth if necessary

7. the area of the playing surface at the olympic stadium in beijing isof a hectare. what area will it occupy on a plan drawn to a scaleof 1: 500?

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels