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Finding the Fourth Proportional to 1,287.98, 1,777.38 and 764

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Solution

The fourth proportional to 1,287.98, 1,777.38 and 764 is: 1,054.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.98 : 1,777.38 = 764 : x
  2. Step 2: Convert to fraction form
    1,287.98/1,777.38 = 764/x
  3. Step 3: Cross multiply
    1,287.98x = 1,777.38 × 764
  4. Step 4: Simplify right side
    1,287.98x = 1,357,918.32
  5. Step 5: Solve for x
    x = 1,357,918.32/1,287.98
  6. Step 6: Final answer
    x = 1,054.30

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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.