That symbol represents "plus out minus". usually represents uncertainty if it is beside a number.
e.g. 3± 0.3 means that the actual answer lies between 2.7 and 3.3
Answer:
berpengalamanfundamentalisme nya codot chihuahua Kukuh
Answer:
Lines BC and F represent perpendicular lines
Step-by-step explanation:
we have
<em>Line BC</em>

the slope of the line BC is 
<em>Line F</em>

the slope of the line F is 
we know that
If two lines are perpendicular, then the product of their slopes is equal to -1
so

we have
-----> slope line BC
-----> slope line F
Find the product of their slopes

therefore
Lines BC and F represent perpendicular lines