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Finding the Fourth Proportional to 688.68, 1,026.36 and 665.28

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Solution

The fourth proportional to 688.68, 1,026.36 and 665.28 is: 991.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.68 : 1,026.36 = 665.28 : x
  2. Step 2: Convert to fraction form
    688.68/1,026.36 = 665.28/x
  3. Step 3: Cross multiply
    688.68x = 1,026.36 × 665.28
  4. Step 4: Simplify right side
    688.68x = 682,816.78
  5. Step 5: Solve for x
    x = 682,816.78/688.68
  6. Step 6: Final answer
    x = 991.49

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.