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Finding the Fourth Proportional to 1,078.84, 1,617.90 and 420.67

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Solution

The fourth proportional to 1,078.84, 1,617.90 and 420.67 is: 630.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,078.84 : 1,617.90 = 420.67 : x
  2. Step 2: Convert to fraction form
    1,078.84/1,617.90 = 420.67/x
  3. Step 3: Cross multiply
    1,078.84x = 1,617.90 × 420.67
  4. Step 4: Simplify right side
    1,078.84x = 680,601.99
  5. Step 5: Solve for x
    x = 680,601.99/1,078.84
  6. Step 6: Final answer
    x = 630.86

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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.