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Finding the Fourth Proportional to 708.72, 978.84 and 578.40

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Solution

The fourth proportional to 708.72, 978.84 and 578.40 is: 798.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.72 : 978.84 = 578.40 : x
  2. Step 2: Convert to fraction form
    708.72/978.84 = 578.40/x
  3. Step 3: Cross multiply
    708.72x = 978.84 × 578.40
  4. Step 4: Simplify right side
    708.72x = 566,161.06
  5. Step 5: Solve for x
    x = 566,161.06/708.72
  6. Step 6: Final answer
    x = 798.85

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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.