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Finding the Fourth Proportional to 670.42, 1,005.81 and 259.57

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Solution

The fourth proportional to 670.42, 1,005.81 and 259.57 is: 389.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.42 : 1,005.81 = 259.57 : x
  2. Step 2: Convert to fraction form
    670.42/1,005.81 = 259.57/x
  3. Step 3: Cross multiply
    670.42x = 1,005.81 × 259.57
  4. Step 4: Simplify right side
    670.42x = 261,078.10
  5. Step 5: Solve for x
    x = 261,078.10/670.42
  6. Step 6: Final answer
    x = 389.42

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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.