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Finding the Fourth Proportional to 691.02, 1,030.80 and 639.36

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Solution

The fourth proportional to 691.02, 1,030.80 and 639.36 is: 953.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.02 : 1,030.80 = 639.36 : x
  2. Step 2: Convert to fraction form
    691.02/1,030.80 = 639.36/x
  3. Step 3: Cross multiply
    691.02x = 1,030.80 × 639.36
  4. Step 4: Simplify right side
    691.02x = 659,052.29
  5. Step 5: Solve for x
    x = 659,052.29/691.02
  6. Step 6: Final answer
    x = 953.74

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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.