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Finding the Fourth Proportional to 90.75, 136.05 and 56.50

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Solution

The fourth proportional to 90.75, 136.05 and 56.50 is: 84.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.75 : 136.05 = 56.50 : x
  2. Step 2: Convert to fraction form
    90.75/136.05 = 56.50/x
  3. Step 3: Cross multiply
    90.75x = 136.05 × 56.50
  4. Step 4: Simplify right side
    90.75x = 7,686.83
  5. Step 5: Solve for x
    x = 7,686.83/90.75
  6. Step 6: Final answer
    x = 84.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.