Okay kiddo, so āryabhaṭa was a really smart man from India who lived a long time ago. He wanted to find a way to measure the angles of things like buildings and bridges, so he came up with something called a sine table.
Now, a sine table is like a big list of numbers that tells you how much of a certain angle is needed to make a right triangle. A right triangle is kinda like a pizza slice that has one corner that is perfectly 90 degrees.
So, let's say you want to measure an angle that is 45 degrees. You can look on āryabhaṭa's sine table and see that the sine of 45 degrees is 0.707106781. That might seem like a funny number, but it's actually really helpful for measuring things accurately.
People used āryabhaṭa's sine table for a long time to help them build things that were sturdy and safe. It's like having a cheat sheet for measuring angles!