Isosceles Triangles
An isosceles triangle is a triangle with at least two congruent sides.
Example 1
This scene in the the movie Harry Potter and the Goblet of Fire takes place in the Great Lake outside of the Hogwarts Castle. At this moment, the Hogwarts students are watching the Durmstrang ship rising up from the water. The isosceles triangle is formed by the ropes that hold up the sail.
"Slowly, magnificently, the ship rose out of the water, gleaming in the moonlight. It had a strangely skeletal look about it, as though it were a resurrected wreck, and the dim, mist lights shimmering at its portholes looked like ghostly eyes. Finally, with a great sloshing noise, the ship emerged entirely, bobbing on the turbulent water, and began to glide toward the bank." -Harry Potter and the Goblet of Fire, Page 246
Example 2
This scene in the movie Harry Potter and the Deathly Hallows, Part 1 takes place at the Lovegoods' house. At this moment, Luna's father is showing Harry, Ron, and Hermione the necklace they have come to question him about, and is telling them about the Deathly Hallows. The outside of the charm on the necklace is an isosceles triangle, and although it looks like an equilateral triangle, it is really isosceles.
"' Well,' said Harry, glancing at Hermione, who nodded encouragingly, 'it's about that symbol you were wearing around your neck at Bill and Fleur's wedding, Mr.Lovegood. We wondered what that meant.' Xenophilius raised his eyebrows. 'Are you referring to the sign of the Deathly Hallows?'" -Harry Potter and the Deathly Hallows, Page 404