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Finding the Fourth Proportional to 978.72, 1,467.90 and 393.99

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Solution

The fourth proportional to 978.72, 1,467.90 and 393.99 is: 590.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.72 : 1,467.90 = 393.99 : x
  2. Step 2: Convert to fraction form
    978.72/1,467.90 = 393.99/x
  3. Step 3: Cross multiply
    978.72x = 1,467.90 × 393.99
  4. Step 4: Simplify right side
    978.72x = 578,337.92
  5. Step 5: Solve for x
    x = 578,337.92/978.72
  6. Step 6: Final answer
    x = 590.91

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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.