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Finding the Fourth Proportional to 1,317.78, 1,818.47 and 813.86

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Solution

The fourth proportional to 1,317.78, 1,818.47 and 813.86 is: 1,123.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,317.78 : 1,818.47 = 813.86 : x
  2. Step 2: Convert to fraction form
    1,317.78/1,818.47 = 813.86/x
  3. Step 3: Cross multiply
    1,317.78x = 1,818.47 × 813.86
  4. Step 4: Simplify right side
    1,317.78x = 1,479,970.90
  5. Step 5: Solve for x
    x = 1,479,970.90/1,317.78
  6. Step 6: Final answer
    x = 1,123.08

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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.