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Finding the Fourth Proportional to 1,291.52, 1,779.28 and 917.90

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Solution

The fourth proportional to 1,291.52, 1,779.28 and 917.90 is: 1,264.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,291.52 : 1,779.28 = 917.90 : x
  2. Step 2: Convert to fraction form
    1,291.52/1,779.28 = 917.90/x
  3. Step 3: Cross multiply
    1,291.52x = 1,779.28 × 917.90
  4. Step 4: Simplify right side
    1,291.52x = 1,633,201.11
  5. Step 5: Solve for x
    x = 1,633,201.11/1,291.52
  6. Step 6: Final answer
    x = 1,264.56

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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.