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Finding the Fourth Proportional to 715.94, 987.96 and 421.38

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Solution

The fourth proportional to 715.94, 987.96 and 421.38 is: 581.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.94 : 987.96 = 421.38 : x
  2. Step 2: Convert to fraction form
    715.94/987.96 = 421.38/x
  3. Step 3: Cross multiply
    715.94x = 987.96 × 421.38
  4. Step 4: Simplify right side
    715.94x = 416,306.58
  5. Step 5: Solve for x
    x = 416,306.58/715.94
  6. Step 6: Final answer
    x = 581.48

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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.