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Finding the Fourth Proportional to 1,217.60, 1,680.32 and 686.56

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Solution

The fourth proportional to 1,217.60, 1,680.32 and 686.56 is: 947.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,217.60 : 1,680.32 = 686.56 : x
  2. Step 2: Convert to fraction form
    1,217.60/1,680.32 = 686.56/x
  3. Step 3: Cross multiply
    1,217.60x = 1,680.32 × 686.56
  4. Step 4: Simplify right side
    1,217.60x = 1,153,640.50
  5. Step 5: Solve for x
    x = 1,153,640.50/1,217.60
  6. Step 6: Final answer
    x = 947.47

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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.