diff --git a/src/c/triangles.c b/src/c/triangles.c
index 5246404..138d801 100644
--- a/src/c/triangles.c
+++ b/src/c/triangles.c
@@ -10,23 +10,10 @@ static void triangle_layer_update_proc(Layer *layer, GContext *ctx) {
 	GRect bounds = layer_get_bounds(layer);
 	graphics_context_set_stroke_color(ctx, tri->color);
 
-	// pick the longest side as the horizontal base
-	uint16_t base_side, left_side;
-	uint8_t left_angle;
-
-	if (tri->side_a >= tri->side_b && tri->side_a >= tri->side_c) {
-		base_side = tri->side_a;
-		left_side = tri->side_c;   // C → A
-		left_angle = tri->angle_B; // at vertex B
-	} else if (tri->side_b >= tri->side_a && tri->side_b >= tri->side_c) {
-		base_side = tri->side_b;
-		left_side = tri->side_c;   // C → B
-		left_angle = tri->angle_A; // at vertex A
-	} else {
-		base_side = tri->side_c;
-		left_side = tri->side_b;   // B → C
-		left_angle = tri->angle_A; // at vertex A
-	}
+	// side_a is always the longest side (horizontal base)
+	uint16_t base_side = tri->side_a;
+	uint16_t left_side = tri->side_c;  // C → A (side c connects vertices B and A)
+	uint8_t left_angle = tri->angle_B; // at vertex B
 
 	// calculate height and horizontal apex offset first
 	int32_t sin_left = sin_lookup(((int32_t)left_angle * TRIG_MAX_ANGLE) / 360);
@@ -93,6 +80,24 @@ TriangleLayer *triangle_layer_create(GRect frame, GColor color) {
 	*(TriangleLayer **)layer_get_data(tri->layer) = tri;
 	layer_set_update_proc(tri->layer, triangle_layer_update_proc);
 
+	// ensure side_a is always longest
+	if (tri->side_b > tri->side_a) {
+		uint16_t tmp_s = tri->side_a;
+		tri->side_a = tri->side_b;
+		tri->side_b = tmp_s;
+		uint8_t tmp_a = tri->angle_A;
+		tri->angle_A = tri->angle_B;
+		tri->angle_B = tmp_a;
+	}
+	if (tri->side_c > tri->side_a) {
+		uint16_t tmp_s = tri->side_a;
+		tri->side_a = tri->side_c;
+		tri->side_c = tmp_s;
+		uint8_t tmp_a = tri->angle_A;
+		tri->angle_A = tri->angle_C;
+		tri->angle_C = tmp_a;
+	}
+
 	return tri;
 }