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Finding the Fourth Proportional to 813.12, 1,127.88 and 784

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Solution

The fourth proportional to 813.12, 1,127.88 and 784 is: 1,087.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.12 : 1,127.88 = 784 : x
  2. Step 2: Convert to fraction form
    813.12/1,127.88 = 784/x
  3. Step 3: Cross multiply
    813.12x = 1,127.88 × 784
  4. Step 4: Simplify right side
    813.12x = 884,257.92
  5. Step 5: Solve for x
    x = 884,257.92/813.12
  6. Step 6: Final answer
    x = 1,087.49

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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.