To identify straight, right, obtuse, and acute angles.

Have students multiply and add.

1.(2x3) + (1x9) =2.(4x5) + (5x2) =3.(8x3) + (6x2) =4.(6x1) + (7x5) =5.(5x3) + (5x3) =

The clock hands suggest an angle. Is the anglestraight, right, obtuse, or acute?

An angle is formed by two rays with a common endpoint. The common endpoint is called thevertex. An angle is usually named by 3 points,the vertex and one on each day.

We say: angle ABC We write: ABC on theclock hands.

A

C B

Notice,in naming an angle, the vertex is always named as the center letter.

Angles are measured in degrees.

So we say, 180 degrees.

We write: 180°

STRAIGHT ANGLE 180°

RIGHT ANGLE 90°

OBTUSE ANGLE

Greater than 90° less than 180°

ACUTE ANGLELess than 90°

What kind of angle does the clock hands suggest?

The clock hands suggest a ________ angle.

LET’S PRACTICE !