How did the geography of the Greek peninsula help them defeat the Persians? Athenian soldiers were able to hide in the valleys.
The Athenians developed a more powerful navy than the Persians.
The Persians were unable to transport supplies into the Greek city-states.
The Persians were unable to cross the mountains.

a or 1 athenian soilders where in valleys

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°