Home / 989.99-1,485.12-638.88

Finding the Fourth Proportional to 989.99, 1,485.12 and 638.88

Calculator

Solution

The fourth proportional to 989.99, 1,485.12 and 638.88 is: 958.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.99 : 1,485.12 = 638.88 : x
  2. Step 2: Convert to fraction form
    989.99/1,485.12 = 638.88/x
  3. Step 3: Cross multiply
    989.99x = 1,485.12 × 638.88
  4. Step 4: Simplify right side
    989.99x = 948,805.50
  5. Step 5: Solve for x
    x = 948,805.50/989.99
  6. Step 6: Final answer
    x = 958.40

Related Problems

Find fourth proportional to 495.00, 742.56 and 319.44
Half scale
Find fourth proportional to 1,979.99, 2,970.23 and 1,277.75
Double scale
Find fourth proportional to 990.99, 1,486.62 and 639.88
Similar ratio
Find fourth proportional to 1,484.99, 2,227.67 and 958.31
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.