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Finding the Fourth Proportional to 1,259.35, 1,887.81 and 643.34

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Solution

The fourth proportional to 1,259.35, 1,887.81 and 643.34 is: 964.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,259.35 : 1,887.81 = 643.34 : x
  2. Step 2: Convert to fraction form
    1,259.35/1,887.81 = 643.34/x
  3. Step 3: Cross multiply
    1,259.35x = 1,887.81 × 643.34
  4. Step 4: Simplify right side
    1,259.35x = 1,214,505.99
  5. Step 5: Solve for x
    x = 1,214,505.99/1,259.35
  6. Step 6: Final answer
    x = 964.39

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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.