If the markings were missing on this quadrilateral, how would you go about verifying what shape it is?

A) Because this is a rectangle, I would show that each vertex is made up with lines that have opposite reciprocal slopes.
B) Because this is a parallelogram, I would show that each vertex is made up with lines that have opposite reciprocal slopes.
C) Because this is a parallelogram, I would show that all four sides are congruent.
D )Because this is a parallelogram, I would show that opposite sides have the same slope.

Option A: Because this is a rectangle, I would show that each vertex is made up with lines that have opposite reciprocal slopes.

Step-by-step explanation:

A rectangle is a quadrilateral with four right angles.

Each right angle is made up of two perpendicular lines forming a vertex

And then proving this that all perpendicular lines have negative reciprocal slope.

It isn't always necessary  to employ the idea of using a parallelogram first although it might be useful.

incomplete question. how do you expect anyone to you when you do not post the question in its entirety?

"it's not the heat, it's the humidity".   that's a partly valid phrase you may have heard in the summer, but it's actually both.   the heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.   this has important considerations for the human body's comfort.   when the body gets too hot, it begins to perspire or sweat to cool itself off.   if the perspiration is not able to evaporate, the body cannot regulate its temperature.   evaporation is a cooling process.   when perspiration is evaporated off the body, it effectively reduces the body's temperature.   when the atmospheric moisture content (i.e. relative humidity) is high, the rate of perspiration from the body decreases.   in other words, the human body feels warmer in humid conditions.   the opposite is true when the relative humidity decreases because the rate of perspiration increases.   the body actually feels cooler in arid conditions.   there is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

step-by-step explanation: