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Finding the Fourth Proportional to 715.38, 987.07 and 420.54

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Solution

The fourth proportional to 715.38, 987.07 and 420.54 is: 580.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.38 : 987.07 = 420.54 : x
  2. Step 2: Convert to fraction form
    715.38/987.07 = 420.54/x
  3. Step 3: Cross multiply
    715.38x = 987.07 × 420.54
  4. Step 4: Simplify right side
    715.38x = 415,097.66
  5. Step 5: Solve for x
    x = 415,097.66/715.38
  6. Step 6: Final answer
    x = 580.25

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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.