Yes the answer is correct
A higher temperature, stiffer materials, and less dense materials increase the speed of sound.
It's not so much a "contradiction" as an approximation. Newton's law of gravitation is an inverse square law whose range is large. It keeps people on the ground, and it keeps satellites in orbit and that's some thousands of km. The force on someone on the ground - their weight - is probably a lot larger than the centripetal force keeping a satellite in orbit (though I've not actually done a calculation to totally verify this). The distance a falling body - a coin, say - travels is very small, and over such a small distance gravity is assumed/approximated to be constant.
Answer:
The perimeter of the rectangle is 60 units.
Explanation:
The perimeter of a rectangle is given by the equation P = 2L + 2W. With W = 12 units and L = 18 units, substituting the values in the equation above:
P = 2(18 units) + 2(12 units)
P = 36 units + 24 units
P = 60 units