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Finding the Fourth Proportional to 0.87, 1.30 and 0.42

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Solution

The fourth proportional to 0.87, 1.30 and 0.42 is: 0.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    0.87 : 1.30 = 0.42 : x
  2. Step 2: Convert to fraction form
    0.87/1.30 = 0.42/x
  3. Step 3: Cross multiply
    0.87x = 1.30 × 0.42
  4. Step 4: Simplify right side
    0.87x = 0.55
  5. Step 5: Solve for x
    x = 0.55/0.87
  6. Step 6: Final answer
    x = 0.63

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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.