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Finding the Fourth Proportional to 890.24, 1,228.46 and 642

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Solution

The fourth proportional to 890.24, 1,228.46 and 642 is: 885.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    890.24 : 1,228.46 = 642 : x
  2. Step 2: Convert to fraction form
    890.24/1,228.46 = 642/x
  3. Step 3: Cross multiply
    890.24x = 1,228.46 × 642
  4. Step 4: Simplify right side
    890.24x = 788,668.11
  5. Step 5: Solve for x
    x = 788,668.11/890.24
  6. Step 6: Final answer
    x = 885.91

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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.