Answer:
#1: 5/8, #2: It is a right triangle, #3 $2: per square foot, #4: 300%
Step-by-step explanation:
#1: If you want the probability of drawing a non-red marble, you need to have the number of non-red marbles divided by the total number of marbles. Since it's a 3 to 5 ratio, and the 5 represents marbles that are white, not red, you can put 5/(5+3), or 5/8 as your answer.
#2: For this one, you need to use the pythagorean theorem, a rule that will be true if it's a right triangle, and false if it's not. It's A² + B² = C², where C is bigger than A and B. To apply this, you can plug 7² + 24² into a calculator, and see whether or not the answer is equal to 25² (which, in this case, it is, meaning that it is a right triangle.)
#3: The idea with this is cancelling out the units until you end up with the units you want. You know how 7897/7897 would still be equal to one, as anything divided by itself is still one? We can use that concept, because multiplying our original value by 1 won't change the value, just the units. Since 1 yard = 3 feet, we can do this: ($18)/(yard²) × (1 yard)/(3 feet) × (1 yard)/(3 feet) = $2/feet²
#4 This one I will use sample values for: let's say our rectangle has a length of 10 inches and a width of 20 inches. That means it's area will be L × W, that is, 10 × 20 = 200 inches². Now lets increase the dimensions by 100%. Our length would become 20 inches, and our width would become 40 inches. That makes L × W = 20 × 40 = 800 inches². Now, to see what percent increase that is from the original, we have to do (800 - 200)/200, that is, 3, or 300%.
Sorry I don't have time to do the last one, but might I suggest that you post the questions individually next time? I just think it might make people less scared to jump into solving one problem than five, so you might get answers sooner =)