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Finding the Fourth Proportional to 715.38, 986.94 and 420.18

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Solution

The fourth proportional to 715.38, 986.94 and 420.18 is: 579.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    715.38 : 986.94 = 420.18 : x
  2. Step 2: Convert to fraction form
    715.38/986.94 = 420.18/x
  3. Step 3: Cross multiply
    715.38x = 986.94 × 420.18
  4. Step 4: Simplify right side
    715.38x = 414,692.45
  5. Step 5: Solve for x
    x = 414,692.45/715.38
  6. Step 6: Final answer
    x = 579.68

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Half scale
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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.