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Finding the Fourth Proportional to 65.42, 90.30 and 42.12

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Solution

The fourth proportional to 65.42, 90.30 and 42.12 is: 58.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.42 : 90.30 = 42.12 : x
  2. Step 2: Convert to fraction form
    65.42/90.30 = 42.12/x
  3. Step 3: Cross multiply
    65.42x = 90.30 × 42.12
  4. Step 4: Simplify right side
    65.42x = 3,802.77
  5. Step 5: Solve for x
    x = 3,802.77/65.42
  6. Step 6: Final answer
    x = 58.13

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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.