50 m vertical tower is braised with a cable secured at the top of the tower and Tide 30 m from the base. What angle does the cable for him with the vertical tower

Brian's school locker has a three-digit combination lock that can be set using the numbers 5 to 9 (including 5 and 9), without repeating a number. the probability that the locker code begins with a prime number is %. the probability that the last digit of the locker code is an odd number is %.

Soil is made of air water organic material minerals weathered rock

Pollution from one country can affect another. for example, south korea is especially affected by pollution and dust storms that come from