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Finding the Fourth Proportional to 714.96, 986.78 and 420.20

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Solution

The fourth proportional to 714.96, 986.78 and 420.20 is: 579.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.96 : 986.78 = 420.20 : x
  2. Step 2: Convert to fraction form
    714.96/986.78 = 420.20/x
  3. Step 3: Cross multiply
    714.96x = 986.78 × 420.20
  4. Step 4: Simplify right side
    714.96x = 414,644.96
  5. Step 5: Solve for x
    x = 414,644.96/714.96
  6. Step 6: Final answer
    x = 579.96

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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.