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Finding the Fourth Proportional to 861.56, 1,189.02 and 628.76

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Solution

The fourth proportional to 861.56, 1,189.02 and 628.76 is: 867.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.56 : 1,189.02 = 628.76 : x
  2. Step 2: Convert to fraction form
    861.56/1,189.02 = 628.76/x
  3. Step 3: Cross multiply
    861.56x = 1,189.02 × 628.76
  4. Step 4: Simplify right side
    861.56x = 747,608.22
  5. Step 5: Solve for x
    x = 747,608.22/861.56
  6. Step 6: Final answer
    x = 867.74

Related Problems

Find fourth proportional to 430.78, 594.51 and 314.38
Half scale
Find fourth proportional to 1,723.12, 2,378.04 and 1,257.52
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.