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Finding the Fourth Proportional to 1,109, 1,530.60 and 643.52

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Solution

The fourth proportional to 1,109, 1,530.60 and 643.52 is: 888.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,109 : 1,530.60 = 643.52 : x
  2. Step 2: Convert to fraction form
    1,109/1,530.60 = 643.52/x
  3. Step 3: Cross multiply
    1,109x = 1,530.60 × 643.52
  4. Step 4: Simplify right side
    1,109x = 984,971.71
  5. Step 5: Solve for x
    x = 984,971.71/1,109
  6. Step 6: Final answer
    x = 888.16

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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.