A 45°-45°-90° set-square and a protractor have the same number of lines of symmetry.
Step 1: What is a line of symmetry?
A line of symmetry is a line that splits a shape into two equal halves. If you fold the shape on that line, both halves match exactly.
Step 2: 45°–45°–90° set-square
This set-square is an isosceles right triangle (two equal sides, one right angle).
If you draw a line from the right-angle corner to the middle of the opposite side (the hypotenuse), the triangle is split into two matching halves.
So, the 45°–45°–90° set-square has 1 line of symmetry.
Step 3: Protractor
A standard protractor is a semicircle with marks from 0° to 180°.
If you draw a straight line through the center and the 90° mark (the middle), the left and right sides are mirror images.
So, the protractor has 1 line of symmetry.
Step 4: Compare
Set-square: 1 line of symmetry.
Protractor: 1 line of symmetry.
Therefore, both have the same number of lines of symmetry.
Answer: True.