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Finding the Fourth Proportional to 1,140.80, 1,711.20 and 728.72

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Solution

The fourth proportional to 1,140.80, 1,711.20 and 728.72 is: 1,093.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,140.80 : 1,711.20 = 728.72 : x
  2. Step 2: Convert to fraction form
    1,140.80/1,711.20 = 728.72/x
  3. Step 3: Cross multiply
    1,140.80x = 1,711.20 × 728.72
  4. Step 4: Simplify right side
    1,140.80x = 1,246,985.66
  5. Step 5: Solve for x
    x = 1,246,985.66/1,140.80
  6. Step 6: Final answer
    x = 1,093.08

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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.