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Finding the Fourth Proportional to 15.85, 21.90 and 15.58

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Solution

The fourth proportional to 15.85, 21.90 and 15.58 is: 21.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.85 : 21.90 = 15.58 : x
  2. Step 2: Convert to fraction form
    15.85/21.90 = 15.58/x
  3. Step 3: Cross multiply
    15.85x = 21.90 × 15.58
  4. Step 4: Simplify right side
    15.85x = 341.20
  5. Step 5: Solve for x
    x = 341.20/15.85
  6. Step 6: Final answer
    x = 21.53

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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.