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Finding the Fourth Proportional to 878.76, 1,212.70 and 485.78

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Solution

The fourth proportional to 878.76, 1,212.70 and 485.78 is: 670.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    878.76 : 1,212.70 = 485.78 : x
  2. Step 2: Convert to fraction form
    878.76/1,212.70 = 485.78/x
  3. Step 3: Cross multiply
    878.76x = 1,212.70 × 485.78
  4. Step 4: Simplify right side
    878.76x = 589,105.41
  5. Step 5: Solve for x
    x = 589,105.41/878.76
  6. Step 6: Final answer
    x = 670.38

Related Problems

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Half scale
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Double scale
Find fourth proportional to 879.76, 1,214.08 and 486.78
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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.