Home / 856.78-1,287.90-534.20

Finding the Fourth Proportional to 856.78, 1,287.90 and 534.20

Calculator

Solution

The fourth proportional to 856.78, 1,287.90 and 534.20 is: 803.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.78 : 1,287.90 = 534.20 : x
  2. Step 2: Convert to fraction form
    856.78/1,287.90 = 534.20/x
  3. Step 3: Cross multiply
    856.78x = 1,287.90 × 534.20
  4. Step 4: Simplify right side
    856.78x = 687,989.74
  5. Step 5: Solve for x
    x = 687,989.74/856.78
  6. Step 6: Final answer
    x = 803.00

Related Problems

Find fourth proportional to 428.39, 643.95 and 267.10
Half scale
Find fourth proportional to 1,713.56, 2,575.80 and 1,068.39
Double scale
Find fourth proportional to 857.78, 1,289.40 and 535.20
Similar ratio
Find fourth proportional to 1,285.17, 1,931.85 and 801.29
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.