7x20=140. 7x2000=14000. The only thing that changes the product of these numbers is the amount of zeros behind the 2. Since the only two numbers that affect the answer is the 7 and the 2. (7x2=14). The number of zeros behind the 2 affect how many zeros will be included in the product.
To find the circumference of a circle you have to multiple the radius by 2 and also by pi. So, to find the radius when given just the circumference, who have to do the reverse operation and divide the circumference by 2 and also by pi to get the answer of 22.92993631, which you could of course round.
When ever you combine different elements the chemical properties change because elements are different , unless you combine the exact same elements.
Question 1:This is a 45-45-90 right triangle. If the leg length is

, then the hypotenuse length will be

.
The leg length of this 45-45-90 right triangle is 8. Multiply that with the square root of 2. You get

. Thus, the last choice is your answer.
Question 2:This triangle can be identified as a 30-60-90 right triangle.
Let's say the smallest leg as a length of

.
Then, the longer leg will have a length of

.
Also, the hypotenuse will have a length of

This triangle follows this format, making it a 30-60-90 right triangle. Thus, the angles are 30, 60, and 90.
Hope this helps! :)