How did early Muslim scholars influence today’s math? People still use Roman numbers.
People still use Hindu-Arabic numbers.
People still use calligraphy to solve problems.
People still use the astrolabe to solve problems.

People still use the astrolabe to solve the problem.

Explanation:

Ahmad ibn Muhammad who lived in present-day Uzbekistan was one of the best astronomers who lived in present-day Baghdad in the ninth century. He mathematically explained the astrolabe (Astronomical instrument for measuring angles). He was also involved in the Tigris Irrigation Canal construction project. During the IX and X centuries, the Arabian Peninsula was the center of science and art in the world.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).