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Finding the Fourth Proportional to 783.38, 1,078.61 and 665.11

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Solution

The fourth proportional to 783.38, 1,078.61 and 665.11 is: 915.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    783.38 : 1,078.61 = 665.11 : x
  2. Step 2: Convert to fraction form
    783.38/1,078.61 = 665.11/x
  3. Step 3: Cross multiply
    783.38x = 1,078.61 × 665.11
  4. Step 4: Simplify right side
    783.38x = 717,388.28
  5. Step 5: Solve for x
    x = 717,388.28/783.38
  6. Step 6: Final answer
    x = 915.76

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.