DrDelMath Intermediate Algebra Examples
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1. Calculate the area of a trapezoid whose height is 3 and whose bases are B = 11 and b = 5.
This first presentation illustrates the proper way of writing the solution to the question.
Use the formula 
.
Note that repeated application of the Transitive Property of Equality tells us without a
doubt the desired area is 24.
The next presentation shows an IMPROPER way of writing the solution to the question.
Use the formula .
Notice that this completely ignores the Transitive Property of Equality.
The final IMPROPER example includes another BAD practice: the infamous box around the
answer.
Use of the box or circle around the "answer" implies several very bad ideas:
