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Finding the Fourth Proportional to 1,107.60, 1,661.40 and 645.90

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Solution

The fourth proportional to 1,107.60, 1,661.40 and 645.90 is: 968.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,107.60 : 1,661.40 = 645.90 : x
  2. Step 2: Convert to fraction form
    1,107.60/1,661.40 = 645.90/x
  3. Step 3: Cross multiply
    1,107.60x = 1,661.40 × 645.90
  4. Step 4: Simplify right side
    1,107.60x = 1,073,098.26
  5. Step 5: Solve for x
    x = 1,073,098.26/1,107.60
  6. Step 6: Final answer
    x = 968.85

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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.