Home / 859.69-1,289.70-311.90

Finding the Fourth Proportional to 859.69, 1,289.70 and 311.90

Calculator

Solution

The fourth proportional to 859.69, 1,289.70 and 311.90 is: 467.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    859.69 : 1,289.70 = 311.90 : x
  2. Step 2: Convert to fraction form
    859.69/1,289.70 = 311.90/x
  3. Step 3: Cross multiply
    859.69x = 1,289.70 × 311.90
  4. Step 4: Simplify right side
    859.69x = 402,250.98
  5. Step 5: Solve for x
    x = 402,250.98/859.69
  6. Step 6: Final answer
    x = 467.90

Related Problems

Find fourth proportional to 429.84, 644.85 and 155.95
Half scale
Find fourth proportional to 1,719.38, 2,579.40 and 623.79
Double scale
Find fourth proportional to 860.69, 1,291.20 and 312.90
Similar ratio
Find fourth proportional to 1,289.53, 1,934.55 and 467.84
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.