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Finding the Fourth Proportional to 693.64, 1,040.80 and 385.72

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Solution

The fourth proportional to 693.64, 1,040.80 and 385.72 is: 578.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    693.64 : 1,040.80 = 385.72 : x
  2. Step 2: Convert to fraction form
    693.64/1,040.80 = 385.72/x
  3. Step 3: Cross multiply
    693.64x = 1,040.80 × 385.72
  4. Step 4: Simplify right side
    693.64x = 401,457.38
  5. Step 5: Solve for x
    x = 401,457.38/693.64
  6. Step 6: Final answer
    x = 578.77

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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.