The purpose of the Dawes severally act of 1887 was to

C.

Explanation:

The Dawes Act of 1887 authorized the federal government to break up tribal lands by partitioning them into individual plots and assimilate Native American Indians into mainstream US society by annihilating their cultural and social traditions.

angle a = 40.6°

step-by-step explanation:

for any right angle triangle we know the pythagoras theorem reveals

hypotenuse² = height²+base²

by this formula we will calculate the length of hypotenuse

h² = 6²+7²

⇒ h =√36+49 = √85 = 9.22

now from the given triangle sin a = height/ hypotenuse

                                                sin a = 6/9.22 = 0.651

therefore

so angle a = 40.6°