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Finding the Fourth Proportional to 65.86, 90.70 and 56.66

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Solution

The fourth proportional to 65.86, 90.70 and 56.66 is: 78.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.86 : 90.70 = 56.66 : x
  2. Step 2: Convert to fraction form
    65.86/90.70 = 56.66/x
  3. Step 3: Cross multiply
    65.86x = 90.70 × 56.66
  4. Step 4: Simplify right side
    65.86x = 5,139.06
  5. Step 5: Solve for x
    x = 5,139.06/65.86
  6. Step 6: Final answer
    x = 78.03

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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.