Let the legs of the triangle be a and b, and the hypotenuse c.
Your first instinct might tell you to use the Pythagorean theorem to go about solving this because

. This works, but it is slow.
The fastest way to solve this is to recognize that the right triangle is a special triangle where the ratio of the sides are 3:4:5. This means that if the legs are 9 and 12, then the hypotenuse is 15 because 3*3 is 9, 3*4 is 12, and 3*5 is 15.
It's the first one. y = 3x
proportional means they are just some multiple of the other.
C. 130,90,130.
#01234, the tenths number stays the same
#56789, the tenths number go up 1 number
Answer:
Step-by-step explanation:
Givens
d1 = d
d2 = 75 - d
r1 = x
r2 = x + 7
t = 3
Equation
x*t + (x + 7)*t = 75
This equation represents the total distance travelled. Neither one of the cyclists have gone 75 miles, but they both have gone distances that equal a total of 75 miles.
Solution
3x + (x + 7)*3 = 75
3x + 3x + 21 = 75
6x + 21 = 75
6x = 54
6x/6 = 54/6
x = 9
Answer
The first cyclist is going 9 miles / hr
The second cyclist is going 16 miles / hour