Home / 856.90-1,285.18-279.64

Finding the Fourth Proportional to 856.90, 1,285.18 and 279.64

Calculator

Solution

The fourth proportional to 856.90, 1,285.18 and 279.64 is: 419.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.90 : 1,285.18 = 279.64 : x
  2. Step 2: Convert to fraction form
    856.90/1,285.18 = 279.64/x
  3. Step 3: Cross multiply
    856.90x = 1,285.18 × 279.64
  4. Step 4: Simplify right side
    856.90x = 359,387.74
  5. Step 5: Solve for x
    x = 359,387.74/856.90
  6. Step 6: Final answer
    x = 419.40

Related Problems

Find fourth proportional to 428.45, 642.59 and 139.82
Half scale
Find fourth proportional to 1,713.80, 2,570.36 and 559.28
Double scale
Find fourth proportional to 857.90, 1,286.68 and 280.64
Similar ratio
Find fourth proportional to 1,285.35, 1,927.77 and 419.46
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.