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Finding the Fourth Proportional to 86.40, 129.63 and 40.71

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Solution

The fourth proportional to 86.40, 129.63 and 40.71 is: 61.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.40 : 129.63 = 40.71 : x
  2. Step 2: Convert to fraction form
    86.40/129.63 = 40.71/x
  3. Step 3: Cross multiply
    86.40x = 129.63 × 40.71
  4. Step 4: Simplify right side
    86.40x = 5,277.24
  5. Step 5: Solve for x
    x = 5,277.24/86.40
  6. Step 6: Final answer
    x = 61.08

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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.