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Finding the Fourth Proportional to 813.18, 1,124.10 and 780.39

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Solution

The fourth proportional to 813.18, 1,124.10 and 780.39 is: 1,078.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.18 : 1,124.10 = 780.39 : x
  2. Step 2: Convert to fraction form
    813.18/1,124.10 = 780.39/x
  3. Step 3: Cross multiply
    813.18x = 1,124.10 × 780.39
  4. Step 4: Simplify right side
    813.18x = 877,236.40
  5. Step 5: Solve for x
    x = 877,236.40/813.18
  6. Step 6: Final answer
    x = 1,078.77

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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.