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Finding the Fourth Proportional to 1,287.54, 1,931.31 and 518.58

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Solution

The fourth proportional to 1,287.54, 1,931.31 and 518.58 is: 777.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.54 : 1,931.31 = 518.58 : x
  2. Step 2: Convert to fraction form
    1,287.54/1,931.31 = 518.58/x
  3. Step 3: Cross multiply
    1,287.54x = 1,931.31 × 518.58
  4. Step 4: Simplify right side
    1,287.54x = 1,001,538.74
  5. Step 5: Solve for x
    x = 1,001,538.74/1,287.54
  6. Step 6: Final answer
    x = 777.87

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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.