There are two types of waves, mechanical and electromagnetic. microwaves, infrared, and radio was are examples of electromagnetic waves. which statement is true about the speed of an electromagnetic wave?
a) it is not affected by changes in media.
b) it is slower in a vacuum than in a medium.
c) in a vacuum, its speed equals half the speed of light.
d) it slows down when it goes from a vacuum to a medium.

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y