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Finding the Fourth Proportional to 1,289.62, 1,779.64 and 730

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Solution

The fourth proportional to 1,289.62, 1,779.64 and 730 is: 1,007.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.62 : 1,779.64 = 730 : x
  2. Step 2: Convert to fraction form
    1,289.62/1,779.64 = 730/x
  3. Step 3: Cross multiply
    1,289.62x = 1,779.64 × 730
  4. Step 4: Simplify right side
    1,289.62x = 1,299,137.20
  5. Step 5: Solve for x
    x = 1,299,137.20/1,289.62
  6. Step 6: Final answer
    x = 1,007.38

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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.