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Finding the Fourth Proportional to 42.99, 64.40 and 39.49

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Solution

The fourth proportional to 42.99, 64.40 and 39.49 is: 59.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.99 : 64.40 = 39.49 : x
  2. Step 2: Convert to fraction form
    42.99/64.40 = 39.49/x
  3. Step 3: Cross multiply
    42.99x = 64.40 × 39.49
  4. Step 4: Simplify right side
    42.99x = 2,543.16
  5. Step 5: Solve for x
    x = 2,543.16/42.99
  6. Step 6: Final answer
    x = 59.16

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.