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Finding the Fourth Proportional to 690.40, 1,036.14 and 666.64

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Solution

The fourth proportional to 690.40, 1,036.14 and 666.64 is: 1,000.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 1,036.14 = 666.64 : x
  2. Step 2: Convert to fraction form
    690.40/1,036.14 = 666.64/x
  3. Step 3: Cross multiply
    690.40x = 1,036.14 × 666.64
  4. Step 4: Simplify right side
    690.40x = 690,732.37
  5. Step 5: Solve for x
    x = 690,732.37/690.40
  6. Step 6: Final answer
    x = 1,000.48

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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.