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Finding the Fourth Proportional to 870.86, 1,209.84 and 862.76

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Solution

The fourth proportional to 870.86, 1,209.84 and 862.76 is: 1,198.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.86 : 1,209.84 = 862.76 : x
  2. Step 2: Convert to fraction form
    870.86/1,209.84 = 862.76/x
  3. Step 3: Cross multiply
    870.86x = 1,209.84 × 862.76
  4. Step 4: Simplify right side
    870.86x = 1,043,801.56
  5. Step 5: Solve for x
    x = 1,043,801.56/870.86
  6. Step 6: Final answer
    x = 1,198.59

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.