Finding the Fourth Proportional to 89.67, 123.80 and 56.49

Step by Step Solution

1. Step 1: Write the proportion equation
   89.67 : 123.80 = 56.49 : x
2. Step 2: Convert to fraction form
   89.67/123.80 = 56.49/x
3. Step 3: Cross multiply
   89.67x = 123.80 × 56.49
4. Step 4: Simplify right side
   89.67x = 6,993.46
5. Step 5: Solve for x
   x = 6,993.46/89.67
6. Step 6: Final answer
   x = 77.99