Can someone answer this please
Questions 19 and 21

Wind speed

Another very old approach to measure wind speed is through the use of a pressure tube

Microbars per second

Earthquake intensity

The currently accepted method is the moment magnitude scale, which measures the total amount of energy released by the earthquake.

The Richter scale is used to determine the intensity of earthquakes

Step-by-step explanation:

sinn is the total amount of students now and m were the students before, you subtract them both (n-m) and divide that by m. then, since to get a percentage from a fraction you have to multiply by 100, your answer should look like this: n-m/m*100

step-by-step explanation:

answer would be 8.64 or s = 11π/4 inches

step-by-step explanation:

s = r θ  

where s = arc length  

r = radius = 3 inches  

θ = central angle in radians = ( π /180)*165  

s = 3(π/180)*165  

= 8.64 inches