How did the japanese forces defeat the invading mongols in the 13th century?

a.they joined forces with an army of samurais.
b. they joined forces with korean warriors.
c. typhoons forced the mongols to retreat.
d. they blocked mongol ships at the shoreline.

B. They joined forces with Korean warriors.

Explanation:

The Mongol people were made up of a group of tribes from the Central Asian steppes. In the early thirteenth century, the warrior Genghis Khan united the tribes and formed an immense empire. At the height of power, its territory extended from present-day China and Korea to eastern Europe. The Mongol empire began to invade Japan around 1274, and established its rule on Japanese territory to the chagrin of the Japanese who wished to free themselves from the clutches of the Mongols and become a free nation again.

The Japanese were resistant to Mongol domination, and this resistance was extremely important in counting the violent expansion of the Mongols across Asia. One reason for Japan's success in defeating the monks in the 13th century was the union between the Japanese samurai and the Korean warriors, who together became a very strong and violent army against the monks.

Since it's a quadrilateral, the measures of the angles have to add up to 360. First, subtract 216 (108×2) from 360 to get 144. Now divide 144 by 4 since you have 4x's that must add to 144. When you do the math, you'll find x=36. So the answer is A.