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Finding the Fourth Proportional to 1,391.80, 2,088 and 417.88

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Solution

The fourth proportional to 1,391.80, 2,088 and 417.88 is: 626.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.80 : 2,088 = 417.88 : x
  2. Step 2: Convert to fraction form
    1,391.80/2,088 = 417.88/x
  3. Step 3: Cross multiply
    1,391.80x = 2,088 × 417.88
  4. Step 4: Simplify right side
    1,391.80x = 872,533.44
  5. Step 5: Solve for x
    x = 872,533.44/1,391.80
  6. Step 6: Final answer
    x = 626.91

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.