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Finding the Fourth Proportional to 811.65, 1,217.40 and 291.69

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Solution

The fourth proportional to 811.65, 1,217.40 and 291.69 is: 437.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.65 : 1,217.40 = 291.69 : x
  2. Step 2: Convert to fraction form
    811.65/1,217.40 = 291.69/x
  3. Step 3: Cross multiply
    811.65x = 1,217.40 × 291.69
  4. Step 4: Simplify right side
    811.65x = 355,103.41
  5. Step 5: Solve for x
    x = 355,103.41/811.65
  6. Step 6: Final answer
    x = 437.51

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Double scale
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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.