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Finding the Fourth Proportional to 1,391.47, 1,920.15 and 761.87

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Solution

The fourth proportional to 1,391.47, 1,920.15 and 761.87 is: 1,051.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,391.47 : 1,920.15 = 761.87 : x
  2. Step 2: Convert to fraction form
    1,391.47/1,920.15 = 761.87/x
  3. Step 3: Cross multiply
    1,391.47x = 1,920.15 × 761.87
  4. Step 4: Simplify right side
    1,391.47x = 1,462,906.62
  5. Step 5: Solve for x
    x = 1,462,906.62/1,391.47
  6. Step 6: Final answer
    x = 1,051.34

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1.5x scale

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.