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Finding the Fourth Proportional to 90.40, 124.71 and 64.15

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Solution

The fourth proportional to 90.40, 124.71 and 64.15 is: 88.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.40 : 124.71 = 64.15 : x
  2. Step 2: Convert to fraction form
    90.40/124.71 = 64.15/x
  3. Step 3: Cross multiply
    90.40x = 124.71 × 64.15
  4. Step 4: Simplify right side
    90.40x = 8,000.15
  5. Step 5: Solve for x
    x = 8,000.15/90.40
  6. Step 6: Final answer
    x = 88.50

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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.