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Finding the Fourth Proportional to 1,239.69, 1,710.85 and 819.30

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Solution

The fourth proportional to 1,239.69, 1,710.85 and 819.30 is: 1,130.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,239.69 : 1,710.85 = 819.30 : x
  2. Step 2: Convert to fraction form
    1,239.69/1,710.85 = 819.30/x
  3. Step 3: Cross multiply
    1,239.69x = 1,710.85 × 819.30
  4. Step 4: Simplify right side
    1,239.69x = 1,401,699.41
  5. Step 5: Solve for x
    x = 1,401,699.41/1,239.69
  6. Step 6: Final answer
    x = 1,130.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.