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Finding the Fourth Proportional to 666.78, 920.14 and 387.01

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Solution

The fourth proportional to 666.78, 920.14 and 387.01 is: 534.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.78 : 920.14 = 387.01 : x
  2. Step 2: Convert to fraction form
    666.78/920.14 = 387.01/x
  3. Step 3: Cross multiply
    666.78x = 920.14 × 387.01
  4. Step 4: Simplify right side
    666.78x = 356,103.38
  5. Step 5: Solve for x
    x = 356,103.38/666.78
  6. Step 6: Final answer
    x = 534.06

Related Problems

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Half scale
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Double scale
Find fourth proportional to 667.78, 921.52 and 388.01
Similar ratio
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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.