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Finding the Fourth Proportional to 714.80, 986.40 and 420.08

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Solution

The fourth proportional to 714.80, 986.40 and 420.08 is: 579.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.80 : 986.40 = 420.08 : x
  2. Step 2: Convert to fraction form
    714.80/986.40 = 420.08/x
  3. Step 3: Cross multiply
    714.80x = 986.40 × 420.08
  4. Step 4: Simplify right side
    714.80x = 414,366.91
  5. Step 5: Solve for x
    x = 414,366.91/714.80
  6. Step 6: Final answer
    x = 579.70

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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.