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Finding the Fourth Proportional to 870.42, 1,200.60 and 555.78

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Solution

The fourth proportional to 870.42, 1,200.60 and 555.78 is: 766.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.42 : 1,200.60 = 555.78 : x
  2. Step 2: Convert to fraction form
    870.42/1,200.60 = 555.78/x
  3. Step 3: Cross multiply
    870.42x = 1,200.60 × 555.78
  4. Step 4: Simplify right side
    870.42x = 667,269.47
  5. Step 5: Solve for x
    x = 667,269.47/870.42
  6. Step 6: Final answer
    x = 766.61

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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.