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Finding the Fourth Proportional to 456.40, 686.04 and 407.80

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Solution

The fourth proportional to 456.40, 686.04 and 407.80 is: 612.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    456.40 : 686.04 = 407.80 : x
  2. Step 2: Convert to fraction form
    456.40/686.04 = 407.80/x
  3. Step 3: Cross multiply
    456.40x = 686.04 × 407.80
  4. Step 4: Simplify right side
    456.40x = 279,767.11
  5. Step 5: Solve for x
    x = 279,767.11/456.40
  6. Step 6: Final answer
    x = 612.99

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.