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Finding the Fourth Proportional to 1,288.89, 1,777.95 and 815.91

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Solution

The fourth proportional to 1,288.89, 1,777.95 and 815.91 is: 1,125.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.89 : 1,777.95 = 815.91 : x
  2. Step 2: Convert to fraction form
    1,288.89/1,777.95 = 815.91/x
  3. Step 3: Cross multiply
    1,288.89x = 1,777.95 × 815.91
  4. Step 4: Simplify right side
    1,288.89x = 1,450,647.18
  5. Step 5: Solve for x
    x = 1,450,647.18/1,288.89
  6. Step 6: Final answer
    x = 1,125.50

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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.