Multiply the numerator and denominator by 7×2 = 14 to eliminate the denominators of those fractions:

Rationalize the denominator by multiplying both numerator and denominator by √10:

Lastly, cancel the common factor of 2 in both the numerator and denominator (which comes from 6 = 2×3 and 490 = 2×245):

The change in temperature for 1 hour would be -5. hope this helps.
Answer:
it`s acute because the angle is less than 90 degrees