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Finding the Fourth Proportional to 670.79, 1,005.45 and 259.80

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Solution

The fourth proportional to 670.79, 1,005.45 and 259.80 is: 389.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    670.79 : 1,005.45 = 259.80 : x
  2. Step 2: Convert to fraction form
    670.79/1,005.45 = 259.80/x
  3. Step 3: Cross multiply
    670.79x = 1,005.45 × 259.80
  4. Step 4: Simplify right side
    670.79x = 261,215.91
  5. Step 5: Solve for x
    x = 261,215.91/670.79
  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.