Home / 457.75-686.58-128.69

Finding the Fourth Proportional to 457.75, 686.58 and 128.69

Calculator

Solution

The fourth proportional to 457.75, 686.58 and 128.69 is: 193.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    457.75 : 686.58 = 128.69 : x
  2. Step 2: Convert to fraction form
    457.75/686.58 = 128.69/x
  3. Step 3: Cross multiply
    457.75x = 686.58 × 128.69
  4. Step 4: Simplify right side
    457.75x = 88,355.98
  5. Step 5: Solve for x
    x = 88,355.98/457.75
  6. Step 6: Final answer
    x = 193.02

Related Problems

Find fourth proportional to 228.87, 343.29 and 64.35
Half scale
Find fourth proportional to 915.49, 1,373.16 and 257.38
Double scale
Find fourth proportional to 458.75, 688.08 and 129.69
Similar ratio
Find fourth proportional to 686.62, 1,029.87 and 193.04
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.