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Finding the Fourth Proportional to 670.34, 1,005.78 and 285.50

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Solution

The fourth proportional to 670.34, 1,005.78 and 285.50 is: 428.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.34 : 1,005.78 = 285.50 : x
  2. Step 2: Convert to fraction form
    670.34/1,005.78 = 285.50/x
  3. Step 3: Cross multiply
    670.34x = 1,005.78 × 285.50
  4. Step 4: Simplify right side
    670.34x = 287,150.19
  5. Step 5: Solve for x
    x = 287,150.19/670.34
  6. Step 6: Final answer
    x = 428.36

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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.