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Finding the Fourth Proportional to 820.77, 1,131.42 and 621.66

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Solution

The fourth proportional to 820.77, 1,131.42 and 621.66 is: 856.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.77 : 1,131.42 = 621.66 : x
  2. Step 2: Convert to fraction form
    820.77/1,131.42 = 621.66/x
  3. Step 3: Cross multiply
    820.77x = 1,131.42 × 621.66
  4. Step 4: Simplify right side
    820.77x = 703,355.27
  5. Step 5: Solve for x
    x = 703,355.27/820.77
  6. Step 6: Final answer
    x = 856.95

Related Problems

Find fourth proportional to 410.38, 565.71 and 310.83
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.