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Finding the Fourth Proportional to 30.90, 42.65 and 23.15

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Solution

The fourth proportional to 30.90, 42.65 and 23.15 is: 31.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.90 : 42.65 = 23.15 : x
  2. Step 2: Convert to fraction form
    30.90/42.65 = 23.15/x
  3. Step 3: Cross multiply
    30.90x = 42.65 × 23.15
  4. Step 4: Simplify right side
    30.90x = 987.51
  5. Step 5: Solve for x
    x = 987.51/30.90
  6. Step 6: Final answer
    x = 31.96

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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.