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Finding the Fourth Proportional to 642.28, 886.68 and 486.76

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Solution

The fourth proportional to 642.28, 886.68 and 486.76 is: 671.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.28 : 886.68 = 486.76 : x
  2. Step 2: Convert to fraction form
    642.28/886.68 = 486.76/x
  3. Step 3: Cross multiply
    642.28x = 886.68 × 486.76
  4. Step 4: Simplify right side
    642.28x = 431,600.36
  5. Step 5: Solve for x
    x = 431,600.36/642.28
  6. Step 6: Final answer
    x = 671.98

Related Problems

Find fourth proportional to 321.14, 443.34 and 243.38
Half scale
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Double scale
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Similar ratio
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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.