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Finding the Fourth Proportional to 688.19, 1,031.00 and 427.50

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Solution

The fourth proportional to 688.19, 1,031.00 and 427.50 is: 640.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.19 : 1,031.00 = 427.50 : x
  2. Step 2: Convert to fraction form
    688.19/1,031.00 = 427.50/x
  3. Step 3: Cross multiply
    688.19x = 1,031.00 × 427.50
  4. Step 4: Simplify right side
    688.19x = 440,750.36
  5. Step 5: Solve for x
    x = 440,750.36/688.19
  6. Step 6: Final answer
    x = 640.45

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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.