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Finding the Fourth Proportional to 45.09, 67.58 and 21

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Solution

The fourth proportional to 45.09, 67.58 and 21 is: 31.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    45.09 : 67.58 = 21 : x
  2. Step 2: Convert to fraction form
    45.09/67.58 = 21/x
  3. Step 3: Cross multiply
    45.09x = 67.58 × 21
  4. Step 4: Simplify right side
    45.09x = 1,419.08
  5. Step 5: Solve for x
    x = 1,419.08/45.09
  6. Step 6: Final answer
    x = 31.47

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.