Home / 831.20-1,245.80-571.20

Finding the Fourth Proportional to 831.20, 1,245.80 and 571.20

Calculator

Solution

The fourth proportional to 831.20, 1,245.80 and 571.20 is: 856.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    831.20 : 1,245.80 = 571.20 : x
  2. Step 2: Convert to fraction form
    831.20/1,245.80 = 571.20/x
  3. Step 3: Cross multiply
    831.20x = 1,245.80 × 571.20
  4. Step 4: Simplify right side
    831.20x = 711,600.96
  5. Step 5: Solve for x
    x = 711,600.96/831.20
  6. Step 6: Final answer
    x = 856.11

Related Problems

Find fourth proportional to 415.60, 622.90 and 285.60
Half scale
Find fourth proportional to 1,662.40, 2,491.60 and 1,142.40
Double scale
Find fourth proportional to 832.20, 1,247.30 and 572.20
Similar ratio
Find fourth proportional to 1,246.80, 1,868.70 and 856.80
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.