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Finding the Fourth Proportional to 92.90, 128.21 and 51.45

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Solution

The fourth proportional to 92.90, 128.21 and 51.45 is: 71.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.90 : 128.21 = 51.45 : x
  2. Step 2: Convert to fraction form
    92.90/128.21 = 51.45/x
  3. Step 3: Cross multiply
    92.90x = 128.21 × 51.45
  4. Step 4: Simplify right side
    92.90x = 6,596.40
  5. Step 5: Solve for x
    x = 6,596.40/92.90
  6. Step 6: Final answer
    x = 71.01

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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.