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Finding the Fourth Proportional to 1,289.16, 1,779.30 and 765.09

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Solution

The fourth proportional to 1,289.16, 1,779.30 and 765.09 is: 1,055.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,289.16 : 1,779.30 = 765.09 : x
  2. Step 2: Convert to fraction form
    1,289.16/1,779.30 = 765.09/x
  3. Step 3: Cross multiply
    1,289.16x = 1,779.30 × 765.09
  4. Step 4: Simplify right side
    1,289.16x = 1,361,324.64
  5. Step 5: Solve for x
    x = 1,361,324.64/1,289.16
  6. Step 6: Final answer
    x = 1,055.98

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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.