Answer:
35 km
Step-by-step explanation:
Since this is a right triangle we can use the Pythagorean theorem
a^2 + b^2 =c^2 where a and b are the legs and c is the hypotenuse
28^2 + 21^2 = c^2
784+441 = c^2
1225 = c^2
Take the square root of each side
sqrt(1225) = sqrt(c^2)
35 = c
The pythagorean theorem states that a^2+b^2=c^2. (The hypotenuse is c)
So, we will plug a and b in.
28^2+21^2=c^2
Then, simplify.
784+441=c^2
1225=c^2
c=35
Therefore, the hypotenuse is 35 km.
