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Finding the Fourth Proportional to 643.80, 965.70 and 631.65

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Solution

The fourth proportional to 643.80, 965.70 and 631.65 is: 947.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 965.70 = 631.65 : x
  2. Step 2: Convert to fraction form
    643.80/965.70 = 631.65/x
  3. Step 3: Cross multiply
    643.80x = 965.70 × 631.65
  4. Step 4: Simplify right side
    643.80x = 609,984.41
  5. Step 5: Solve for x
    x = 609,984.41/643.80
  6. Step 6: Final answer
    x = 947.48

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Double scale
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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.