Home / 285.78-428.60-80.30

Finding the Fourth Proportional to 285.78, 428.60 and 80.30

Calculator

Solution

The fourth proportional to 285.78, 428.60 and 80.30 is: 120.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    285.78 : 428.60 = 80.30 : x
  2. Step 2: Convert to fraction form
    285.78/428.60 = 80.30/x
  3. Step 3: Cross multiply
    285.78x = 428.60 × 80.30
  4. Step 4: Simplify right side
    285.78x = 34,416.58
  5. Step 5: Solve for x
    x = 34,416.58/285.78
  6. Step 6: Final answer
    x = 120.43

Related Problems

Find fourth proportional to 142.89, 214.30 and 40.15
Half scale
Find fourth proportional to 571.56, 857.20 and 160.60
Double scale
Find fourth proportional to 286.78, 430.10 and 81.30
Similar ratio
Find fourth proportional to 428.67, 642.90 and 120.45
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.