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Finding the Fourth Proportional to 860.70, 1,291.05 and 515.10

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Solution

The fourth proportional to 860.70, 1,291.05 and 515.10 is: 772.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    860.70 : 1,291.05 = 515.10 : x
  2. Step 2: Convert to fraction form
    860.70/1,291.05 = 515.10/x
  3. Step 3: Cross multiply
    860.70x = 1,291.05 × 515.10
  4. Step 4: Simplify right side
    860.70x = 665,019.86
  5. Step 5: Solve for x
    x = 665,019.86/860.70
  6. Step 6: Final answer
    x = 772.65

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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 (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.