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Finding the Fourth Proportional to 870.10, 1,200.81 and 520.78

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Solution

The fourth proportional to 870.10, 1,200.81 and 520.78 is: 718.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.10 : 1,200.81 = 520.78 : x
  2. Step 2: Convert to fraction form
    870.10/1,200.81 = 520.78/x
  3. Step 3: Cross multiply
    870.10x = 1,200.81 × 520.78
  4. Step 4: Simplify right side
    870.10x = 625,357.83
  5. Step 5: Solve for x
    x = 625,357.83/870.10
  6. Step 6: Final answer
    x = 718.72

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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.