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Finding the Fourth Proportional to 870.78, 1,201.72 and 477.80

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Solution

The fourth proportional to 870.78, 1,201.72 and 477.80 is: 659.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.78 : 1,201.72 = 477.80 : x
  2. Step 2: Convert to fraction form
    870.78/1,201.72 = 477.80/x
  3. Step 3: Cross multiply
    870.78x = 1,201.72 × 477.80
  4. Step 4: Simplify right side
    870.78x = 574,181.82
  5. Step 5: Solve for x
    x = 574,181.82/870.78
  6. Step 6: Final answer
    x = 659.39

Related Problems

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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.