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Finding the Fourth Proportional to 689.60, 1,031.36 and 613.08

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Solution

The fourth proportional to 689.60, 1,031.36 and 613.08 is: 916.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.60 : 1,031.36 = 613.08 : x
  2. Step 2: Convert to fraction form
    689.60/1,031.36 = 613.08/x
  3. Step 3: Cross multiply
    689.60x = 1,031.36 × 613.08
  4. Step 4: Simplify right side
    689.60x = 632,306.19
  5. Step 5: Solve for x
    x = 632,306.19/689.60
  6. Step 6: Final answer
    x = 916.92

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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.