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Finding the Fourth Proportional to 1,378.78, 2,066.49 and 647.38

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Solution

The fourth proportional to 1,378.78, 2,066.49 and 647.38 is: 970.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.78 : 2,066.49 = 647.38 : x
  2. Step 2: Convert to fraction form
    1,378.78/2,066.49 = 647.38/x
  3. Step 3: Cross multiply
    1,378.78x = 2,066.49 × 647.38
  4. Step 4: Simplify right side
    1,378.78x = 1,337,804.30
  5. Step 5: Solve for x
    x = 1,337,804.30/1,378.78
  6. Step 6: Final answer
    x = 970.28

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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.