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Finding the Fourth Proportional to 869.90, 1,305.28 and 540.76

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Solution

The fourth proportional to 869.90, 1,305.28 and 540.76 is: 811.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.90 : 1,305.28 = 540.76 : x
  2. Step 2: Convert to fraction form
    869.90/1,305.28 = 540.76/x
  3. Step 3: Cross multiply
    869.90x = 1,305.28 × 540.76
  4. Step 4: Simplify right side
    869.90x = 705,838.60
  5. Step 5: Solve for x
    x = 705,838.60/869.90
  6. Step 6: Final answer
    x = 811.40

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.