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Finding the Fourth Proportional to 91.50, 126.30 and 57

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Solution

The fourth proportional to 91.50, 126.30 and 57 is: 78.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.50 : 126.30 = 57 : x
  2. Step 2: Convert to fraction form
    91.50/126.30 = 57/x
  3. Step 3: Cross multiply
    91.50x = 126.30 × 57
  4. Step 4: Simplify right side
    91.50x = 7,199.10
  5. Step 5: Solve for x
    x = 7,199.10/91.50
  6. Step 6: Final answer
    x = 78.68

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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.