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Finding the Fourth Proportional to 686.45, 947.26 and 387.70

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Solution

The fourth proportional to 686.45, 947.26 and 387.70 is: 535.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.45 : 947.26 = 387.70 : x
  2. Step 2: Convert to fraction form
    686.45/947.26 = 387.70/x
  3. Step 3: Cross multiply
    686.45x = 947.26 × 387.70
  4. Step 4: Simplify right side
    686.45x = 367,252.70
  5. Step 5: Solve for x
    x = 367,252.70/686.45
  6. Step 6: Final answer
    x = 535.00

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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.