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Finding the Fourth Proportional to 645.30, 890.06 and 396.77

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Solution

The fourth proportional to 645.30, 890.06 and 396.77 is: 547.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.30 : 890.06 = 396.77 : x
  2. Step 2: Convert to fraction form
    645.30/890.06 = 396.77/x
  3. Step 3: Cross multiply
    645.30x = 890.06 × 396.77
  4. Step 4: Simplify right side
    645.30x = 353,142.67
  5. Step 5: Solve for x
    x = 353,142.67/645.30
  6. Step 6: Final answer
    x = 547.25

Related Problems

Find fourth proportional to 322.65, 445.03 and 198.38
Half scale
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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.