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Finding the Fourth Proportional to 669.66, 1,005.21 and 285.18

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Solution

The fourth proportional to 669.66, 1,005.21 and 285.18 is: 428.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.66 : 1,005.21 = 285.18 : x
  2. Step 2: Convert to fraction form
    669.66/1,005.21 = 285.18/x
  3. Step 3: Cross multiply
    669.66x = 1,005.21 × 285.18
  4. Step 4: Simplify right side
    669.66x = 286,665.79
  5. Step 5: Solve for x
    x = 286,665.79/669.66
  6. Step 6: Final answer
    x = 428.08

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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.