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Finding the Fourth Proportional to 690.40, 953.76 and 638.56

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Solution

The fourth proportional to 690.40, 953.76 and 638.56 is: 882.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    690.40 : 953.76 = 638.56 : x
  2. Step 2: Convert to fraction form
    690.40/953.76 = 638.56/x
  3. Step 3: Cross multiply
    690.40x = 953.76 × 638.56
  4. Step 4: Simplify right side
    690.40x = 609,032.99
  5. Step 5: Solve for x
    x = 609,032.99/690.40
  6. Step 6: Final answer
    x = 882.15

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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.