Perpendicular Line 0A3Fd0

1. **State the problem:** We need to construct a 90° angle on a line segment $AB$ where $AB = 7$ cm. 2. **Draw the line segment:** Draw a straight line segment $AB$ of length $7$ cm. 3. **Construct the perpendicular:** To construct a 90° angle on $AB$, we need to draw a line perpendicular to $AB$ at point $A$ (or $B$). 4. **Using a compass and straightedge:** - Place the compass point at $A$ and draw an arc that crosses $AB$ at two points. - Without changing the compass width, place the compass point on each intersection and draw two arcs above $AB$ that intersect. - Draw a straight line from $A$ through the intersection of the arcs. This line is perpendicular to $AB$. 5. **Result:** The angle formed between $AB$ and the constructed line at $A$ is $90^\circ$. This completes the construction of a $90^\circ$ angle on line $AB$ with length $7$ cm.