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Finding the Fourth Proportional to 355.12, 489.80 and 215.19

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Solution

The fourth proportional to 355.12, 489.80 and 215.19 is: 296.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    355.12 : 489.80 = 215.19 : x
  2. Step 2: Convert to fraction form
    355.12/489.80 = 215.19/x
  3. Step 3: Cross multiply
    355.12x = 489.80 × 215.19
  4. Step 4: Simplify right side
    355.12x = 105,400.60
  5. Step 5: Solve for x
    x = 105,400.60/355.12
  6. Step 6: Final answer
    x = 296.80

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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.