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Finding the Fourth Proportional to 1,378.68, 2,066.94 and 647.88

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Solution

The fourth proportional to 1,378.68, 2,066.94 and 647.88 is: 971.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.68 : 2,066.94 = 647.88 : x
  2. Step 2: Convert to fraction form
    1,378.68/2,066.94 = 647.88/x
  3. Step 3: Cross multiply
    1,378.68x = 2,066.94 × 647.88
  4. Step 4: Simplify right side
    1,378.68x = 1,339,129.09
  5. Step 5: Solve for x
    x = 1,339,129.09/1,378.68
  6. Step 6: Final answer
    x = 971.31

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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.