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Finding the Fourth Proportional to 1,115.27, 1,539.06 and 643.16

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Solution

The fourth proportional to 1,115.27, 1,539.06 and 643.16 is: 887.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,115.27 : 1,539.06 = 643.16 : x
  2. Step 2: Convert to fraction form
    1,115.27/1,539.06 = 643.16/x
  3. Step 3: Cross multiply
    1,115.27x = 1,539.06 × 643.16
  4. Step 4: Simplify right side
    1,115.27x = 989,854.13
  5. Step 5: Solve for x
    x = 989,854.13/1,115.27
  6. Step 6: Final answer
    x = 887.55

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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.