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Finding the Fourth Proportional to 90.61, 124.90 and 61.45

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Solution

The fourth proportional to 90.61, 124.90 and 61.45 is: 84.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.61 : 124.90 = 61.45 : x
  2. Step 2: Convert to fraction form
    90.61/124.90 = 61.45/x
  3. Step 3: Cross multiply
    90.61x = 124.90 × 61.45
  4. Step 4: Simplify right side
    90.61x = 7,675.11
  5. Step 5: Solve for x
    x = 7,675.11/90.61
  6. Step 6: Final answer
    x = 84.70

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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.