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Finding the Fourth Proportional to 890.90, 1,337.20 and 428.99

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Solution

The fourth proportional to 890.90, 1,337.20 and 428.99 is: 643.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.90 : 1,337.20 = 428.99 : x
  2. Step 2: Convert to fraction form
    890.90/1,337.20 = 428.99/x
  3. Step 3: Cross multiply
    890.90x = 1,337.20 × 428.99
  4. Step 4: Simplify right side
    890.90x = 573,649.84
  5. Step 5: Solve for x
    x = 573,649.84/890.90
  6. Step 6: Final answer
    x = 643.90

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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.