Home / 856.96-1,285.44-280

Finding the Fourth Proportional to 856.96, 1,285.44 and 280

Calculator

Solution

The fourth proportional to 856.96, 1,285.44 and 280 is: 420

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.96 : 1,285.44 = 280 : x
  2. Step 2: Convert to fraction form
    856.96/1,285.44 = 280/x
  3. Step 3: Cross multiply
    856.96x = 1,285.44 × 280
  4. Step 4: Simplify right side
    856.96x = 359,923.20
  5. Step 5: Solve for x
    x = 359,923.20/856.96
  6. Step 6: Final answer
    x = 420

Related Problems

Find fourth proportional to 428.48, 642.72 and 140
Half scale
Find fourth proportional to 1,713.92, 2,570.88 and 560
Double scale
Find fourth proportional to 857.96, 1,286.94 and 281
Similar ratio
Find fourth proportional to 1,285.44, 1,928.16 and 420
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.