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Finding the Fourth Proportional to 628.75, 867.87 and 421.75

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Solution

The fourth proportional to 628.75, 867.87 and 421.75 is: 582.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    628.75 : 867.87 = 421.75 : x
  2. Step 2: Convert to fraction form
    628.75/867.87 = 421.75/x
  3. Step 3: Cross multiply
    628.75x = 867.87 × 421.75
  4. Step 4: Simplify right side
    628.75x = 366,024.17
  5. Step 5: Solve for x
    x = 366,024.17/628.75
  6. Step 6: Final answer
    x = 582.15

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Find fourth proportional to 314.38, 433.94 and 210.88
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.