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Finding the Fourth Proportional to 491.88, 678.12 and 386.55

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Solution

The fourth proportional to 491.88, 678.12 and 386.55 is: 532.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.88 : 678.12 = 386.55 : x
  2. Step 2: Convert to fraction form
    491.88/678.12 = 386.55/x
  3. Step 3: Cross multiply
    491.88x = 678.12 × 386.55
  4. Step 4: Simplify right side
    491.88x = 262,127.29
  5. Step 5: Solve for x
    x = 262,127.29/491.88
  6. Step 6: Final answer
    x = 532.91

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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.