Answer:
The pressure in mmHg is 1253 (option C)
Explanation:
Two quantities are directly proportional if when multiplying or dividing one of them by a number, the other is multiplied or divided by that number. In other words, the magnitudes are directly proportional when one magnitude increases and so does the other in the same proportion; or when one magnitude decreases and so does the other in the same proportion.
The rule of three or is a way of solving proportionality problems between three known values and an unknown value, which can be applied to directly proportional quantities as follows:
a ⇒ b
c ⇒ x
So 
where a, b and c are data and x is the unknown value to be calculated.
In this case, knowing that 1 Torr = 1 mmHg, the rule of three can be applied as follows: if 1 torr is equal to 1 mmHg, 1253 torr is equal to how many mmHg?

pressure= 1253 mmHg
<u><em>The pressure in mmHg is 1253 (option C)</em></u>
Answer:
Explanation:
SF4 forms a trigonal bipyramidal shape and its molecular shape is that of a "see-saw".
Since sulfur is in 3rd period, it violates the octet rule and has more than 8 electrons accompanying its valence shell.
Here's a picture of lewis structure and electron geometry.