She put 12.8 in place of 11.9 in the formula of the triangle. Then the correct option is A.
<h3>What is Geometry?</h3>
It deals with the size of geometry, region, and density of the different forms both 2D and 3D.
Regina’s work to find the surface area of a square pyramid from its net is shown below.
A square pyramid. The square base has side lengths of 9.4 inches. The triangular sides have a height of 11.9 inches.
Surface area of the pyramid = 4 [one-half (9.4) (12.8)] + 9.4² = 329 square inches
Then the error done by Regina will be
She should have used One-half (9.4) (11.9) to represent the area of a single triangle.
Then the correct option is A.
More about the geometry link is given below.
brainly.com/question/7558603
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