Answer: I'm pretty sure it would be -7º Celcius for it to be cancelled. Hope it helped!
99.7% encompasses about 3 standard deviations either side of the mean.
82 ±3*2 = (76, 88)
About 99.7% of the values lie between 76 and 88.
The answer is: 
The explanation is shown below:
1. Cynthia rounds the number, which is identified as
, to one decimal place and the result is 6.3.
2. Based on this, we know that
could have been between 6.25 and 6.35. Therefore, the error interval for
is given by:

Where
indicates that the value 6.25 is included and
indicates that the value 6.35 is not included (Because if
had been exactly 6.35, Cynthia would round up to 6.4).
The answer to this question would be: B. JK and LM meet at a right angle.
The reversed T symbol in this question means "perpendicular". That means the JK and LM line have 90-degree angle difference. A straight angle is 180 degree and right angle mean 90 degrees.
A perpendicular line should be in the same plane and intersect each other.