Question

triangle a is reflected in a horizontal mirror line. which way round would it be after this reflection, would it be like triangle b or triangle c?

Explanation:

Step1: Understand Reflection Over Horizontal Line

A horizontal mirror line (like a horizontal axis) reflects a figure such that the vertical positions of points are reversed (top - bottom flip), while horizontal positions remain the same in terms of left - right (but the orientation flips vertically). For a triangle, when reflected over a horizontal line, the "top" and "bottom" vertices (or sides) swap in a way that preserves the horizontal alignment but flips the vertical orientation.

Looking at Triangle A: It has a left - hand vertical side (from top to bottom) and a slanted side to the right - hand bottom vertex. When we reflect over a horizontal line, the bottom vertex (lowest point) should move to the top - like position relative to the horizontal mirror, and the top vertices (left and right top) should move to the bottom - like position relative to the mirror.

Step2: Compare with Triangles B and C

• Triangle B: The slanted side is going from top - left to bottom - right, which is a different orientation than the reflection of A.
• Triangle C: After a horizontal reflection, the vertical flip of Triangle A (where the bottom vertex moves up and the top vertices move down in a way that the horizontal alignment of the base is preserved) results in a triangle that looks like Triangle C. The base of Triangle A (the top horizontal side) when reflected over a horizontal line becomes the bottom horizontal side, and the bottom vertex (vertical side's bottom) becomes the top - like vertex, which matches the shape of Triangle C.

Answer:

C