There is a direct variation between x² and y, when x = 7 and y = 49. Find x when y = 100?

200, -200

50, -50

10, -10

None of these

Given the direct variation between x² and y, we can write:

x² = ky

where k is the constant of variation.

Step 1: Find the constant of variation k

When x = 7 and y = 49:

7² = k * 49

49 = k * 49

k = 1

Step 2: Write the equation of variation

x² = y

Step 3: Find x when y = 100

x² = 100

x = ±√100

x = ±10

The answer is: 10, -10.