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Finding the Fourth Proportional to 890.12, 1,228.27 and 491.78

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Solution

The fourth proportional to 890.12, 1,228.27 and 491.78 is: 678.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.12 : 1,228.27 = 491.78 : x
  2. Step 2: Convert to fraction form
    890.12/1,228.27 = 491.78/x
  3. Step 3: Cross multiply
    890.12x = 1,228.27 × 491.78
  4. Step 4: Simplify right side
    890.12x = 604,038.62
  5. Step 5: Solve for x
    x = 604,038.62/890.12
  6. Step 6: Final answer
    x = 678.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.