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Finding the Fourth Proportional to 285.34, 428 and 138.98

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Solution

The fourth proportional to 285.34, 428 and 138.98 is: 208.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.34 : 428 = 138.98 : x
  2. Step 2: Convert to fraction form
    285.34/428 = 138.98/x
  3. Step 3: Cross multiply
    285.34x = 428 × 138.98
  4. Step 4: Simplify right side
    285.34x = 59,483.44
  5. Step 5: Solve for x
    x = 59,483.44/285.34
  6. Step 6: Final answer
    x = 208.47

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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.