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Finding the Fourth Proportional to 1,007.21, 1,511.07 and 390.74

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Solution

The fourth proportional to 1,007.21, 1,511.07 and 390.74 is: 586.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,007.21 : 1,511.07 = 390.74 : x
  2. Step 2: Convert to fraction form
    1,007.21/1,511.07 = 390.74/x
  3. Step 3: Cross multiply
    1,007.21x = 1,511.07 × 390.74
  4. Step 4: Simplify right side
    1,007.21x = 590,435.49
  5. Step 5: Solve for x
    x = 590,435.49/1,007.21
  6. Step 6: Final answer
    x = 586.21

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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.