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Finding the Fourth Proportional to 815.38, 1,125.12 and 667.78

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Solution

The fourth proportional to 815.38, 1,125.12 and 667.78 is: 921.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.38 : 1,125.12 = 667.78 : x
  2. Step 2: Convert to fraction form
    815.38/1,125.12 = 667.78/x
  3. Step 3: Cross multiply
    815.38x = 1,125.12 × 667.78
  4. Step 4: Simplify right side
    815.38x = 751,332.63
  5. Step 5: Solve for x
    x = 751,332.63/815.38
  6. Step 6: Final answer
    x = 921.45

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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.