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Finding the Fourth Proportional to 890.15, 1,336.08 and 428.24

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Solution

The fourth proportional to 890.15, 1,336.08 and 428.24 is: 642.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.15 : 1,336.08 = 428.24 : x
  2. Step 2: Convert to fraction form
    890.15/1,336.08 = 428.24/x
  3. Step 3: Cross multiply
    890.15x = 1,336.08 × 428.24
  4. Step 4: Simplify right side
    890.15x = 572,165.44
  5. Step 5: Solve for x
    x = 572,165.44/890.15
  6. Step 6: Final answer
    x = 642.78

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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.