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Finding the Fourth Proportional to 978.51, 1,467.95 and 285.15

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Solution

The fourth proportional to 978.51, 1,467.95 and 285.15 is: 427.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.51 : 1,467.95 = 285.15 : x
  2. Step 2: Convert to fraction form
    978.51/1,467.95 = 285.15/x
  3. Step 3: Cross multiply
    978.51x = 1,467.95 × 285.15
  4. Step 4: Simplify right side
    978.51x = 418,584.52
  5. Step 5: Solve for x
    x = 418,584.52/978.51
  6. Step 6: Final answer
    x = 427.78

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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.