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Finding the Fourth Proportional to 1,114.70, 1,538.34 and 642.72

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Solution

The fourth proportional to 1,114.70, 1,538.34 and 642.72 is: 886.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,114.70 : 1,538.34 = 642.72 : x
  2. Step 2: Convert to fraction form
    1,114.70/1,538.34 = 642.72/x
  3. Step 3: Cross multiply
    1,114.70x = 1,538.34 × 642.72
  4. Step 4: Simplify right side
    1,114.70x = 988,710.98
  5. Step 5: Solve for x
    x = 988,710.98/1,114.70
  6. Step 6: Final answer
    x = 886.98

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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.