C=5/9(f−32) the equation above shows how temperature f, measured in degrees fahrenheit, relates to a temperature c, measured in degrees celsius. based on the equation, which of the following must be true? 1) a temperature increase of 1 degree fahrenheit is equivalent to a temperature increase of 59 degree celsius. 2) a temperature increase of 1 degree celsius is equivalent to a temperature increase of 1.8 degrees fahrenheit. 3) a temperature increase of 59 degree fahrenheit is equivalent to a temperature increase of 1 degree celsius. a) i only b) ii only c) iii only d) i and ii only