Sorry, I'm no help because I have no idea how to do those!
FIRST PROBLEM AS GENIUS!!!
The 45-45-90 triangle theorem states that each leg equals x, and the hypotenuse equals

. Using this, we can find that the height is 10. Take the average of the lengths to get l = 27.
The area = 270.
4/6 = 14/21
When using cross product always multiply the left fractions numerator times the right side fractions denominator and the left side fractions denominator times the right side fractions numerator
4×21 = 6×14
84=84
They are equivalent because they both equal 84
Well, things like sporting events, or freak storms are measured in days, or weeks. Depends. For weather, it could be hurricanes, tornado's, or even large fires(not quite weather, but could be)