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Finding the Fourth Proportional to 61.70, 91.90 and 61.40

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Solution

The fourth proportional to 61.70, 91.90 and 61.40 is: 91.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.70 : 91.90 = 61.40 : x
  2. Step 2: Convert to fraction form
    61.70/91.90 = 61.40/x
  3. Step 3: Cross multiply
    61.70x = 91.90 × 61.40
  4. Step 4: Simplify right side
    61.70x = 5,642.66
  5. Step 5: Solve for x
    x = 5,642.66/61.70
  6. Step 6: Final answer
    x = 91.45

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.