For each problem, use the scale factor to set up a proportion and solve for the missing length. Will give brainliest I actually wanna go to bed :(

Which equation represents a proportional relationship that has a constant of proportionality equal to 1/5

Agroup of three friends order a combo meal which includes two slices of pizza and a drink each drink is priced at $2.50 the combined total of $31.50 how much is the cost of a slice of pizza

Awavelength of 610 nm was found to be the most intense wavelength emitted by copper. answer the following questions about this wavelength of light. a) what is this wavelength in cm? b) what is the frequency that corresponds to this wavelength? c) what is the energy of light of this wavelength? d) what is the wavenumber corresponding to this wavelength?