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Finding the Fourth Proportional to 91.71, 137.40 and 65.91

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Solution

The fourth proportional to 91.71, 137.40 and 65.91 is: 98.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.71 : 137.40 = 65.91 : x
  2. Step 2: Convert to fraction form
    91.71/137.40 = 65.91/x
  3. Step 3: Cross multiply
    91.71x = 137.40 × 65.91
  4. Step 4: Simplify right side
    91.71x = 9,055.51
  5. Step 5: Solve for x
    x = 9,055.51/91.71
  6. Step 6: Final answer
    x = 98.74

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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.