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Finding the Fourth Proportional to 1,119.64, 1,678.90 and 425.78

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Solution

The fourth proportional to 1,119.64, 1,678.90 and 425.78 is: 638.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,119.64 : 1,678.90 = 425.78 : x
  2. Step 2: Convert to fraction form
    1,119.64/1,678.90 = 425.78/x
  3. Step 3: Cross multiply
    1,119.64x = 1,678.90 × 425.78
  4. Step 4: Simplify right side
    1,119.64x = 714,842.04
  5. Step 5: Solve for x
    x = 714,842.04/1,119.64
  6. Step 6: Final answer
    x = 638.46

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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.