Finding the Fourth Proportional to 61.31, 91.99 and 42.07

Step by Step Solution

1. Step 1: Write the proportion equation
   61.31 : 91.99 = 42.07 : x
2. Step 2: Convert to fraction form
   61.31/91.99 = 42.07/x
3. Step 3: Cross multiply
   61.31x = 91.99 × 42.07
4. Step 4: Simplify right side
   61.31x = 3,869.81
5. Step 5: Solve for x
   x = 3,869.81/61.31
6. Step 6: Final answer
   x = 63.12