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Finding the Fourth Proportional to 1,279, 1,918.78 and 457.32

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Solution

The fourth proportional to 1,279, 1,918.78 and 457.32 is: 686.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279 : 1,918.78 = 457.32 : x
  2. Step 2: Convert to fraction form
    1,279/1,918.78 = 457.32/x
  3. Step 3: Cross multiply
    1,279x = 1,918.78 × 457.32
  4. Step 4: Simplify right side
    1,279x = 877,496.47
  5. Step 5: Solve for x
    x = 877,496.47/1,279
  6. Step 6: Final answer
    x = 686.08

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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.