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Finding the Fourth Proportional to 929.78, 1,283.10 and 515.78

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Solution

The fourth proportional to 929.78, 1,283.10 and 515.78 is: 711.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    929.78 : 1,283.10 = 515.78 : x
  2. Step 2: Convert to fraction form
    929.78/1,283.10 = 515.78/x
  3. Step 3: Cross multiply
    929.78x = 1,283.10 × 515.78
  4. Step 4: Simplify right side
    929.78x = 661,797.32
  5. Step 5: Solve for x
    x = 661,797.32/929.78
  6. Step 6: Final answer
    x = 711.78

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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.