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Finding the Fourth Proportional to 709.64, 978.68 and 499.74

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Solution

The fourth proportional to 709.64, 978.68 and 499.74 is: 689.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.64 : 978.68 = 499.74 : x
  2. Step 2: Convert to fraction form
    709.64/978.68 = 499.74/x
  3. Step 3: Cross multiply
    709.64x = 978.68 × 499.74
  4. Step 4: Simplify right side
    709.64x = 489,085.54
  5. Step 5: Solve for x
    x = 489,085.54/709.64
  6. Step 6: Final answer
    x = 689.20

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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.