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Finding the Fourth Proportional to 1,378.40, 2,065.98 and 648.59

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Solution

The fourth proportional to 1,378.40, 2,065.98 and 648.59 is: 972.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.40 : 2,065.98 = 648.59 : x
  2. Step 2: Convert to fraction form
    1,378.40/2,065.98 = 648.59/x
  3. Step 3: Cross multiply
    1,378.40x = 2,065.98 × 648.59
  4. Step 4: Simplify right side
    1,378.40x = 1,339,973.97
  5. Step 5: Solve for x
    x = 1,339,973.97/1,378.40
  6. Step 6: Final answer
    x = 972.12

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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.