Ok a actually have two questions..
1. which of the following expressions is written in scientific notation?
a) 73.4x10^5
b) 0.09x10^7
c) 80x10^3
d) 4.22x10^-3

2. which of the following is 0.708 written in scientific notation?
a) 7.08x10^-8
b) 7.8x10^-8
c) 708x10^-10
d) 70.08x10^-9

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

The measures of the legs of a right triangle are 15m and 20m . what is the length of the hypotenuse

Billie holiday sells children's clothing for sara vaughn's toddler shop. baby blankets sell for $29.99 after a markup rate based on cost of 109%. find the cost and the markup.