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Finding the Fourth Proportional to 691.70, 1,036.20 and 643.10

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Solution

The fourth proportional to 691.70, 1,036.20 and 643.10 is: 963.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.70 : 1,036.20 = 643.10 : x
  2. Step 2: Convert to fraction form
    691.70/1,036.20 = 643.10/x
  3. Step 3: Cross multiply
    691.70x = 1,036.20 × 643.10
  4. Step 4: Simplify right side
    691.70x = 666,380.22
  5. Step 5: Solve for x
    x = 666,380.22/691.70
  6. Step 6: Final answer
    x = 963.39

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1.5x scale

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.