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Finding the Fourth Proportional to 870.20, 1,200.90 and 538.79

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Solution

The fourth proportional to 870.20, 1,200.90 and 538.79 is: 743.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.20 : 1,200.90 = 538.79 : x
  2. Step 2: Convert to fraction form
    870.20/1,200.90 = 538.79/x
  3. Step 3: Cross multiply
    870.20x = 1,200.90 × 538.79
  4. Step 4: Simplify right side
    870.20x = 647,032.91
  5. Step 5: Solve for x
    x = 647,032.91/870.20
  6. Step 6: Final answer
    x = 743.55

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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.