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Finding the Fourth Proportional to 90.77, 136.16 and 39.40

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Solution

The fourth proportional to 90.77, 136.16 and 39.40 is: 59.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.77 : 136.16 = 39.40 : x
  2. Step 2: Convert to fraction form
    90.77/136.16 = 39.40/x
  3. Step 3: Cross multiply
    90.77x = 136.16 × 39.40
  4. Step 4: Simplify right side
    90.77x = 5,364.17
  5. Step 5: Solve for x
    x = 5,364.17/90.77
  6. Step 6: Final answer
    x = 59.10

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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.