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Finding the Fourth Proportional to 621.40, 931.55 and 312.99

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Solution

The fourth proportional to 621.40, 931.55 and 312.99 is: 469.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    621.40 : 931.55 = 312.99 : x
  2. Step 2: Convert to fraction form
    621.40/931.55 = 312.99/x
  3. Step 3: Cross multiply
    621.40x = 931.55 × 312.99
  4. Step 4: Simplify right side
    621.40x = 291,566.62
  5. Step 5: Solve for x
    x = 291,566.62/621.40
  6. Step 6: Final answer
    x = 469.21

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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.