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Finding the Fourth Proportional to 840.75, 1,160.28 and 491.64

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Solution

The fourth proportional to 840.75, 1,160.28 and 491.64 is: 678.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.75 : 1,160.28 = 491.64 : x
  2. Step 2: Convert to fraction form
    840.75/1,160.28 = 491.64/x
  3. Step 3: Cross multiply
    840.75x = 1,160.28 × 491.64
  4. Step 4: Simplify right side
    840.75x = 570,440.06
  5. Step 5: Solve for x
    x = 570,440.06/840.75
  6. Step 6: Final answer
    x = 678.49

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Find fourth proportional to 420.38, 580.14 and 245.82
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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.