Temperature
Part of the Fundamentals section of Coddy's Algebra journey. Lesson 59 of 64.
The formula F = 9/5 C + 32 converts a Celsius temperature to Fahrenheit. Water boils at 212 °F. To find that temperature in Celsius, substitute F = 212:
212 = 9/5 C + 32
Subtract 32 from both sides to get 180 = 9/5 C. Then multiply both sides by 5/9 to undo the fraction coefficient, which gives C = 100. Water boils at 100 °C, so the answer is right.
The equation 212 = 9/5 C + 32 is a two-step equation with a fraction coefficient, and the letter is on the right side. Look at what is done to C: it is multiplied by 9/5, and then 32 is added. Undo those two steps in reverse order: subtract 32 first, then multiply by 5/9.
Challenge
MediumA warm day is 68 °F. Substituting into the formula gives 68 = 9/5 C + 32. Solve for C.
Try it yourself
Solve for C
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Fundamentals
1What an Equation Is
The EquationFinding the UnknownThe Same to Both SidesSolved Means AloneRecap: First Equations4Two-Step Equations
Two Layers to UndoSubtract, Then DivideAdd, Then DivideA Division InsideNegatives in Two StepsRecap: Two-Step Equations2One-Step Equations
Undoing AdditionUndoing SubtractionUndoing MultiplicationUndoing DivisionInverse OperationsRecap: One-Step Equations5Tidying First
Like TermsTerms and Numbers MixedThe Distributive PropertyDistributing a SubtractionTidy, Then SolveRecap: Tidying First