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Finding the Fourth Proportional to 690.40, 951.78 and 493.12

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Solution

The fourth proportional to 690.40, 951.78 and 493.12 is: 679.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 951.78 = 493.12 : x
  2. Step 2: Convert to fraction form
    690.40/951.78 = 493.12/x
  3. Step 3: Cross multiply
    690.40x = 951.78 × 493.12
  4. Step 4: Simplify right side
    690.40x = 469,341.75
  5. Step 5: Solve for x
    x = 469,341.75/690.40
  6. Step 6: Final answer
    x = 679.81

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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.