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Finding the Fourth Proportional to 91.47, 136.54 and 77.80

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Solution

The fourth proportional to 91.47, 136.54 and 77.80 is: 116.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.47 : 136.54 = 77.80 : x
  2. Step 2: Convert to fraction form
    91.47/136.54 = 77.80/x
  3. Step 3: Cross multiply
    91.47x = 136.54 × 77.80
  4. Step 4: Simplify right side
    91.47x = 10,622.81
  5. Step 5: Solve for x
    x = 10,622.81/91.47
  6. Step 6: Final answer
    x = 116.13

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.