Home / 647.68-971.92-339.78

Finding the Fourth Proportional to 647.68, 971.92 and 339.78

Calculator

Solution

The fourth proportional to 647.68, 971.92 and 339.78 is: 509.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    647.68 : 971.92 = 339.78 : x
  2. Step 2: Convert to fraction form
    647.68/971.92 = 339.78/x
  3. Step 3: Cross multiply
    647.68x = 971.92 × 339.78
  4. Step 4: Simplify right side
    647.68x = 330,238.98
  5. Step 5: Solve for x
    x = 330,238.98/647.68
  6. Step 6: Final answer
    x = 509.88

Related Problems

Find fourth proportional to 323.84, 485.96 and 169.89
Half scale
Find fourth proportional to 1,295.36, 1,943.84 and 679.56
Double scale
Find fourth proportional to 648.68, 973.42 and 340.78
Similar ratio
Find fourth proportional to 971.52, 1,457.88 and 509.67
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.