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Finding the Fourth Proportional to 65.90, 90.74 and 56.68

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Solution

The fourth proportional to 65.90, 90.74 and 56.68 is: 78.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.90 : 90.74 = 56.68 : x
  2. Step 2: Convert to fraction form
    65.90/90.74 = 56.68/x
  3. Step 3: Cross multiply
    65.90x = 90.74 × 56.68
  4. Step 4: Simplify right side
    65.90x = 5,143.14
  5. Step 5: Solve for x
    x = 5,143.14/65.90
  6. Step 6: Final answer
    x = 78.04

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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.