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Finding the Fourth Proportional to 1,029.40, 1,421.10 and 636.64

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Solution

The fourth proportional to 1,029.40, 1,421.10 and 636.64 is: 878.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,029.40 : 1,421.10 = 636.64 : x
  2. Step 2: Convert to fraction form
    1,029.40/1,421.10 = 636.64/x
  3. Step 3: Cross multiply
    1,029.40x = 1,421.10 × 636.64
  4. Step 4: Simplify right side
    1,029.40x = 904,729.10
  5. Step 5: Solve for x
    x = 904,729.10/1,029.40
  6. Step 6: Final answer
    x = 878.89

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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.