## Pentagram Triangles

How many triangles are formed?

## Magic Triangle

Place the digits 1 through 9 in the circles in a very special way.

## Counting Triangles

Determine the number of triangles in the diagram.

## Non-Overlapping Triangles

Use three lines to form as many triangles as possible.

## Lining Up to Find Triangles

Draw lines to find the largest amount of triangles.

## Toothpick Transfer

Readjust a diagram to form a number of triangles.

## Hidden Triangles

Count the number of triangles in a picture.

## SAM

Explore Symmetry with Altitudes and Medians.

## Triangular Numbers

Explore the sequence of triangular numbers.

## Triangles Inscribed Inside Triangles

Explore properties of triangles constructed using the midpoint of given triangles.

## Constructing Isosceles Triangles

Explain how to construct isosceles triangles.

## Tiling

Tile a square patio with triangular tiles.

## Slicing Triangles

Cut any given triangle into triangles of equal area.

## Prime Scalene

Find the smallest possible perimeter of a scalene triangle.

## Triangles Inside a Trapezoid

Use the area of a triangle to transform a trapezoid into different quadrilaterals.

## Area Formulas

Investigate the areas of triangles in a variety of ways.

## Interactive Pythagoras

Use the concept of area to demonstrate the Pythagorean Theorem.

## Planting Trees

Help a farmer plant four trees.

## Half As Much May Be Right

Explore triangles inscribed in semicircles.

## Balancing the Triangular Totter

Locate the center of mass of a triangle.

## To Be or Not to Be

Determine the necessary conditions to create a triangle.

## Outside Looking In

Identify the sum of the exterior angles in a triangle.

## Remotely Interior

Compare exterior angles with remote interior angles.

## Shark Attack!

Find the best path from the inside of a triangle to its sides.

## Sum It Up!

Explore the sum of interior angles of a triangle.

## Classified Information

Investigate combining triangle classifications based on length and angle measure.

## In or Out?

Determine the location of the altitudes in a triangle.