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Finding the Fourth Proportional to 1,313.91, 1,812.15 and 815.61

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Solution

The fourth proportional to 1,313.91, 1,812.15 and 815.61 is: 1,124.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,313.91 : 1,812.15 = 815.61 : x
  2. Step 2: Convert to fraction form
    1,313.91/1,812.15 = 815.61/x
  3. Step 3: Cross multiply
    1,313.91x = 1,812.15 × 815.61
  4. Step 4: Simplify right side
    1,313.91x = 1,478,007.66
  5. Step 5: Solve for x
    x = 1,478,007.66/1,313.91
  6. Step 6: Final answer
    x = 1,124.89

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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.