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Finding the Fourth Proportional to 65.50, 91 and 64.87

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Solution

The fourth proportional to 65.50, 91 and 64.87 is: 90.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.50 : 91 = 64.87 : x
  2. Step 2: Convert to fraction form
    65.50/91 = 64.87/x
  3. Step 3: Cross multiply
    65.50x = 91 × 64.87
  4. Step 4: Simplify right side
    65.50x = 5,903.17
  5. Step 5: Solve for x
    x = 5,903.17/65.50
  6. Step 6: Final answer
    x = 90.12

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.