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Finding the Fourth Proportional to 1,259.74, 1,887.96 and 643.60

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Solution

The fourth proportional to 1,259.74, 1,887.96 and 643.60 is: 964.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,259.74 : 1,887.96 = 643.60 : x
  2. Step 2: Convert to fraction form
    1,259.74/1,887.96 = 643.60/x
  3. Step 3: Cross multiply
    1,259.74x = 1,887.96 × 643.60
  4. Step 4: Simplify right side
    1,259.74x = 1,215,091.06
  5. Step 5: Solve for x
    x = 1,215,091.06/1,259.74
  6. Step 6: Final answer
    x = 964.56

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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.