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Finding the Fourth Proportional to 753.80, 1,128.34 and 419.78

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Solution

The fourth proportional to 753.80, 1,128.34 and 419.78 is: 628.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    753.80 : 1,128.34 = 419.78 : x
  2. Step 2: Convert to fraction form
    753.80/1,128.34 = 419.78/x
  3. Step 3: Cross multiply
    753.80x = 1,128.34 × 419.78
  4. Step 4: Simplify right side
    753.80x = 473,646.82
  5. Step 5: Solve for x
    x = 473,646.82/753.80
  6. Step 6: Final answer
    x = 628.35

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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.