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Finding the Fourth Proportional to 1,217.81, 1,680.47 and 686.66

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Solution

The fourth proportional to 1,217.81, 1,680.47 and 686.66 is: 947.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,217.81 : 1,680.47 = 686.66 : x
  2. Step 2: Convert to fraction form
    1,217.81/1,680.47 = 686.66/x
  3. Step 3: Cross multiply
    1,217.81x = 1,680.47 × 686.66
  4. Step 4: Simplify right side
    1,217.81x = 1,153,913.25
  5. Step 5: Solve for x
    x = 1,153,913.25/1,217.81
  6. Step 6: Final answer
    x = 947.53

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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.