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Finding the Fourth Proportional to 492, 678.78 and 305.46

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Solution

The fourth proportional to 492, 678.78 and 305.46 is: 421.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    492 : 678.78 = 305.46 : x
  2. Step 2: Convert to fraction form
    492/678.78 = 305.46/x
  3. Step 3: Cross multiply
    492x = 678.78 × 305.46
  4. Step 4: Simplify right side
    492x = 207,340.14
  5. Step 5: Solve for x
    x = 207,340.14/492
  6. Step 6: Final answer
    x = 421.42

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.