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Finding the Fourth Proportional to 30.78, 45.90 and 30.66

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Solution

The fourth proportional to 30.78, 45.90 and 30.66 is: 45.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.78 : 45.90 = 30.66 : x
  2. Step 2: Convert to fraction form
    30.78/45.90 = 30.66/x
  3. Step 3: Cross multiply
    30.78x = 45.90 × 30.66
  4. Step 4: Simplify right side
    30.78x = 1,407.29
  5. Step 5: Solve for x
    x = 1,407.29/30.78
  6. Step 6: Final answer
    x = 45.72

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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.