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Finding the Fourth Proportional to 688.81, 1,035 and 643.81

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Solution

The fourth proportional to 688.81, 1,035 and 643.81 is: 967.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.81 : 1,035 = 643.81 : x
  2. Step 2: Convert to fraction form
    688.81/1,035 = 643.81/x
  3. Step 3: Cross multiply
    688.81x = 1,035 × 643.81
  4. Step 4: Simplify right side
    688.81x = 666,343.35
  5. Step 5: Solve for x
    x = 666,343.35/688.81
  6. Step 6: Final answer
    x = 967.39

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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.