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Finding the Fourth Proportional to 669.75, 1,005.17 and 345.21

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Solution

The fourth proportional to 669.75, 1,005.17 and 345.21 is: 518.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    669.75 : 1,005.17 = 345.21 : x
  2. Step 2: Convert to fraction form
    669.75/1,005.17 = 345.21/x
  3. Step 3: Cross multiply
    669.75x = 1,005.17 × 345.21
  4. Step 4: Simplify right side
    669.75x = 346,994.74
  5. Step 5: Solve for x
    x = 346,994.74/669.75
  6. Step 6: Final answer
    x = 518.10

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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.