This is a right triangle. To find the length of the hypotenuse a^2 + b^2 = c^2.
21^2 + 18^2 = c^2
441 + 324 = c^2
765 = c^2
27.66 km
Yes - they have to be similar. Since they are using the same line as the hypotenuse, the ratio of the other two sides are in the same ratio (ie, the slope of the line), the 3 inner angles will be the same. Thus, the triangles will be similar.
Answer:
B. 
Step-by-step explanation:
Total number of students surveyed = 420
Of which only
prefer rap.
So, the number of people who like rap is the product of the fraction of people who prefer rap and the total number of students.

The number of students that prefer rap is 105
So the equation is
.
The number of positive roots is the number of changes of signs there are, then decrease by 2 each time and stop when you get to 1 or 0
negative roots, sub every x with -x and reevaluate, count change of signs
decrease by 2 each time and stop when you get to 1 or 0
y=+2x⁵-x⁴-2x³+4x²+x-2
+,-,-,+,+,-
1 2 3
3 or 1 positive roots
replace x with -x ( baically flip all signs of odd powerd numbers)
y=-2x⁵-x⁴+2x³+4x²-x-2
-,-,+,+,-,-
1 2
2 or 0 negative roots
3 or 1 positive roots
2 or 0 negative roots
2nd option is answer
33•3 is 99, so the answer is 3