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Finding the Fourth Proportional to 1,115.14, 1,538.70 and 642.93

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Solution

The fourth proportional to 1,115.14, 1,538.70 and 642.93 is: 887.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,115.14 : 1,538.70 = 642.93 : x
  2. Step 2: Convert to fraction form
    1,115.14/1,538.70 = 642.93/x
  3. Step 3: Cross multiply
    1,115.14x = 1,538.70 × 642.93
  4. Step 4: Simplify right side
    1,115.14x = 989,276.39
  5. Step 5: Solve for x
    x = 989,276.39/1,115.14
  6. Step 6: Final answer
    x = 887.13

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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.