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Finding the Fourth Proportional to 714.76, 986.36 and 420.20

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Solution

The fourth proportional to 714.76, 986.36 and 420.20 is: 579.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    714.76 : 986.36 = 420.20 : x
  2. Step 2: Convert to fraction form
    714.76/986.36 = 420.20/x
  3. Step 3: Cross multiply
    714.76x = 986.36 × 420.20
  4. Step 4: Simplify right side
    714.76x = 414,468.47
  5. Step 5: Solve for x
    x = 414,468.47/714.76
  6. Step 6: Final answer
    x = 579.87

Related Problems

Find fourth proportional to 357.38, 493.18 and 210.10
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.