**LESSON PLAN 4**

**School Unit : SMP N 1 BOYOLALI**

**Subject : Mathematics**

**Class/Semester : VIII/I**

**A. ****Standard of Competency :**

Understand the algebra forms, relations, functions, and linear equations.

B. **Basic of Competency :**

Determining gradient, straight line equation, and straight line graph.

**C. ****Indicators :**

1. Know definition and determine gradient of straight line in many form.

2. Determine the equation of straight line which passing one point by certain of gradient.

3. Determine the equation of straight line which passing two point by certain of gradient.

D. **Tipe allocation **: 2 x 40 minutes

**E. ****Learning achievement :**

After studying this lesson, student will be able to :

a. Explain definition of gradient of straight line.

b. Determine the gradient of straight line if coordinate of one point are known.

c. Determine equations of straight line if the equations points that passed are known.

d. Determine the gradient of straight line if coordinate of two points are known.

e. Determine equations of straight line if one points and gradient are know.

f. Determine equations of straight line if two points that passed are known.

**F. ****Topics :**

Straight line.

**G. ****Methods, approach, and model :**

Learning method : direct interaction and cooperative.

Method : orally, dill, discussion and task assignment

**H. ****Learning activities :**

Preface

a. Remind how to draw the point on coordinate plane and also on the contrary

b. Inform learning achievement

Main activities :

a. Explain definition of gradient of straight line.

b. Student do exercise in pairs, teacher help group that have a problem.

c. Explain how to find gradient of straight line if coordinate of two points are known.

d. Student do exercise in group.

e. Asks some groups to presents their result. Other groups give responses. Teacher guides to the correct answer.

Closing :

a. Teacher guides student to make conclusion.

b. Teacher gives homework.

**I. ****Tool and references :**

Text book, white board, grid paper, ruler, and computer.

**J. ****Assessment :**

**Kind : Formative test discussion result.**

**Form : Essay**

1.

0 |

y |

1 |

2 |

3 |

4 |

5 |

6 |

7 |

8 |

9 |

10 |

1 |

2 |

3 |

4 |

5 |

6 |

7 |

8 |

9 |

10 |

A (1,6) |

B (3,2) |

y |

The gradient of straight line that through points A (1,6) and B (3,2)

2. Determine the gradient of straight line that through point A (-4,3) and B (8,-5)!

3. Determine the gradient of straight line :

a. y = 2x – 3

b. y + 4x = 1

c. 7x – 3y + 2 = 0

4. Determine the equation of straight line that has gradient -1 and through point (0,8)

5. Determine the equation of straight line that through point (3,4) and points (5,4) ?