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Finding the Fourth Proportional to 485.45, 669.76 and 310.76

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Solution

The fourth proportional to 485.45, 669.76 and 310.76 is: 428.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.45 : 669.76 = 310.76 : x
  2. Step 2: Convert to fraction form
    485.45/669.76 = 310.76/x
  3. Step 3: Cross multiply
    485.45x = 669.76 × 310.76
  4. Step 4: Simplify right side
    485.45x = 208,130.49
  5. Step 5: Solve for x
    x = 208,130.49/485.45
  6. Step 6: Final answer
    x = 428.74

Related Problems

Find fourth proportional to 242.72, 334.88 and 155.38
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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.