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Finding the Fourth Proportional to 1,288.09, 1,777.55 and 720.92

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Solution

The fourth proportional to 1,288.09, 1,777.55 and 720.92 is: 994.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.09 : 1,777.55 = 720.92 : x
  2. Step 2: Convert to fraction form
    1,288.09/1,777.55 = 720.92/x
  3. Step 3: Cross multiply
    1,288.09x = 1,777.55 × 720.92
  4. Step 4: Simplify right side
    1,288.09x = 1,281,458.85
  5. Step 5: Solve for x
    x = 1,281,458.85/1,288.09
  6. Step 6: Final answer
    x = 994.85

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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.