# data[].attributes.body
corresponding parts of congruent triangles are congruent

# data[].attributes.attachment_link.description
The sum of the measures of the interior angles of a triangle is 180°.

# data[].attributes.attachment_link.readable_text
Different Angles have different names:

An Obtuse Angle is more than 90° but less than 180°

All the angles below are obtuse angles:

Which Angle?

Remember to look carefully at which angle you are being asked to name.

The obtuse angle is the smaller angle.
It is more than 90° and less than 180°.

The smaller angle is an Obtuse Angle,
but the larger angle is a Reflex Angle

If you choose the larger angle you have a Reflex Angle (more than 180° but less than 360°) instead:

1782, 3282, 9153, 9154, 1781, 3286, 3287, 8985, 809, 810

# data[].attributes.attachment_link.description
Note the special symbol like a box in the angle. If we see this, it is a right angle. The 90° is rarely written in. If we see the box in the corner, we are being told it is a right angle.

# data[].attributes.attachment_link.description
Types of Angles Right Angles Obtuse Angles Straight Angle Reflex Angles Angles On a Straight Line Angles Around a Point Degrees (Angle) Geometry Index

# data[].attributes.attachment_link.title
The Hypotenuse Leg Theorem for proving congruent triangles only works for right triangles, so the 1st thing you need to do is..

# data[].attributes.attachment_link.description
How to prove congruent right triangles using the hypotenuse leg theorem.

# data[].attributes.body
If 2 angles and a nonincluded side of one triangle are congruent to 2 angles and the corresponding nonincluded side of another triangle, then the triangles are congruent.

# data[].attributes.body
If 2 angles and the included side of one triangle are congruent to 2 angles and the included side of another triangle, then the 2 triangles are congruent

# data[].attributes.body
If the and the included angle of one triangle are congruent to 2 sides and the included angle of another triangle, then the 2 triangles are congruent

# data[].attributes.body
If the three sides of one triangle are congruent to the three sides of another triangle, then the two triangles are congruent.

# data[].attributes.attachment_link.readable_text
For a triangle:

The exterior angle d equals the angles a plus b.

The exterior angle d is greater than angle a, or angle b.

Example:

The exterior angle is 35° + 62° = 97°

Why?

Because the interior angles of a triangle add to 180°, and angles c+d also add to 180°:

Works For Any Triangle's Exterior Angle

Example:

The exterior angle is 40° + 27° = 67°

Example: How big is angle d?

We can't calculate exactly, but we can say:

# data[].attributes.attachment_link.description
For a triangle: The exterior angle d equals the angles a plus b. The exterior angle d is greater than angle a, or angle b.

# data[].attributes.body
triangle with all equal sides and angles

# data[].attributes.body
triangle with 2 congruent sides and angles

# data[].attributes.body
triangle with 3 unequal sides