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Finding the Fourth Proportional to 90.47, 124.75 and 61.40

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Solution

The fourth proportional to 90.47, 124.75 and 61.40 is: 84.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.47 : 124.75 = 61.40 : x
  2. Step 2: Convert to fraction form
    90.47/124.75 = 61.40/x
  3. Step 3: Cross multiply
    90.47x = 124.75 × 61.40
  4. Step 4: Simplify right side
    90.47x = 7,659.65
  5. Step 5: Solve for x
    x = 7,659.65/90.47
  6. Step 6: Final answer
    x = 84.67

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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.