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Finding the Fourth Proportional to 643.49, 965.15 and 253.78

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Solution

The fourth proportional to 643.49, 965.15 and 253.78 is: 380.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.49 : 965.15 = 253.78 : x
  2. Step 2: Convert to fraction form
    643.49/965.15 = 253.78/x
  3. Step 3: Cross multiply
    643.49x = 965.15 × 253.78
  4. Step 4: Simplify right side
    643.49x = 244,935.77
  5. Step 5: Solve for x
    x = 244,935.77/643.49
  6. Step 6: Final answer
    x = 380.64

Related Problems

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Half scale
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Double scale
Find fourth proportional to 644.49, 966.65 and 254.78
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.