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Finding the Fourth Proportional to 885.48, 1,221.12 and 638.40

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Solution

The fourth proportional to 885.48, 1,221.12 and 638.40 is: 880.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    885.48 : 1,221.12 = 638.40 : x
  2. Step 2: Convert to fraction form
    885.48/1,221.12 = 638.40/x
  3. Step 3: Cross multiply
    885.48x = 1,221.12 × 638.40
  4. Step 4: Simplify right side
    885.48x = 779,563.01
  5. Step 5: Solve for x
    x = 779,563.01/885.48
  6. Step 6: Final answer
    x = 880.38

Related Problems

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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.