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Finding the Fourth Proportional to 1,114.85, 1,538.57 and 642.88

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Solution

The fourth proportional to 1,114.85, 1,538.57 and 642.88 is: 887.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,114.85 : 1,538.57 = 642.88 : x
  2. Step 2: Convert to fraction form
    1,114.85/1,538.57 = 642.88/x
  3. Step 3: Cross multiply
    1,114.85x = 1,538.57 × 642.88
  4. Step 4: Simplify right side
    1,114.85x = 989,108.82
  5. Step 5: Solve for x
    x = 989,108.82/1,114.85
  6. Step 6: Final answer
    x = 887.21

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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.