12. Flowcharts Classify Triangles by Sides

Logical operators are used to combine conditions in decision-making.

Logical Operators

Operator	Name	Description
AND	Logical AND	True only if both conditions are true
OR	Logical OR	True if at least one condition is true
NOT	Logical NOT	Reverses the truth value (true → false)

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The flowchart below checks to see if a triangle has all sides equal, or just 2 sides equal, and classifies it accordingly.

The pseudocode below checks to see if a triangles has all sides equal, or just 2 sides equal, or none equal, and classifies it accordingly.

ALGORITHM triangleType()

BEGIN
    INPUT sideA, sideB, sideC
    IF sideA = sideB AND sideB = sideC THEN
        PRINT "Equilateral triangle."
    ELSEIF sideA = sideB OR sideB = sideC OR sideA = sideC THEN
        PRINT "Isosceles triangle."
    ELSE
        PRINT "Scalene triangle."
    ENDIF
END

Tasks

1. In the pseudocode, in the IF statement above, which logical operator is used to see if all 3 sides are of equal length?

2. In the pseudocode, in the ELSEIF statement above, what is the most number of sides that can be equal?

Q1

In the pseudocode, in the IF statement above, which logical operator is used to see if all 3 sides are of equal length?

‘’ code-block:: none

AND

Q2

In the pseudocode, in the ELSEIF statement above, what is the most number of sides that can be equal?

‘’ code-block:: none

2 sides, since 3 sides has been covered in the IF statement and decided to be false.