In science class, Mr. Brodell’s students were directed to weigh a 400-gram mass on the balance scale. Erika weighed the object and reported 420 grams. What is the percent error of the weight of Erika's object?

Type your response in the box below.

The formula for percent error is given by:

Percent error = (|measured value - actual value| / actual value) x 100

In this case, the measured value is 420 grams and the actual value is 400 grams (since that was the weight the students were directed to measure). Substituting these values into the formula, we can calculate the percent error:

Percent error = (|420 - 400| / 400) x 100
= (20 / 400) x 100
= 0.05 x 100
= 5

Thus, the percent error of Erika's weight measurement is 5%.