# Linder Geo Ch 9

## 10 terms

### The Area Postulate

Every polygonal region has a positive number called its area such that 1) congruent triangles have equal areas and 2) the area of a polygonal region is equal to the sum of the areas of its nonoverlapping parts.

### Postulate 9

The area of a rectangle is the product of its base and altitude

### Corollary to Postulate 9

The area of a square is the square of its side.

### Theorem 38

The area of a right triangle is half the product of its legs.

### Theorem 39

The area of a triangle is half the product of any base and corresponding altitude.

### Corollary to Theorem 39

Triangles with equal bases and equal altitudes have equal areas

### Theorem 40

The area of a parallelogram is the product of any base and corresponding altitude

### Theorem 41

The area of a trapezoid is half the product of its altitude and the sum of its bases.

### The Pythagorean Theorem

The square of the hypotenuse of a right triangle is equal to the sum of the squares of its legs.

### Theorem 43

If the Square of one side of a triangle is equal to the sum of the squares of the other two sides, the triangle is a right triangle.