Formulating Equations

K. Coleman

Cobb 6th Grade Campus

GPISD

TEKS Objective 6.5

  Patterns, relationships, and algebraic thinking. The student uses letters to represent an unknown in an equation. The student is expected to formulate an equation from a problem situation.

Purpose

• develop the ability to collect data and record data in a table

• recognize what varies in an experiment

• name the independent and dependent variables in a problem

Focus Activity 1

• The table below shows the relationship between the number of hours worked and the wages earned. What ratio describes this relationship?

Hours 1 2 3 4

Wages $8 $16 $24 $32

Give a rule for this relationship

Focus Activity 2

• The table below shows the relationship between the mileage and the fuel used in a new Ford Explorer. What ratio describes this relationship?

Mileage 64 96 128 160

Fuel (gal) 2 3 4 5

Give a rule for this relationship

Instructions

• Use triangle and square pattern blocks to model houses

• Have students model House 1, 2, 3, and 4.• Students should identify how many pieces

it takes to model each house.• Identify the ratio of triangles to squares,

squares to triangles, and triangles to house number.

• Organize the data into a table.

Instruction cont’d

•Determine a rule for your data.

•Use your rule to determine the number of pieces for House 5 and House 12

•Determine if the ratio is the same for house 5 and house 12

•Identify any other rule you can determine from your data

Guided Practice• Julie is making cookies. It takes two cups of

raisins for four dozen cookies. If she is making twenty four dozen cookies for the church fair, how many cups of raisins will she need?

• Paul uses 9 straws and 6 pieces of clay to make 1 triangular prism. He uses 18 straws and 12 pieces of clay to make 2 triangular prisms. How many straws and pieces of clay will he need to make 5 triangular prisms?

• Find a rule for each problem above.

Independent Practice

• Students are to go to the following website:

Perform the exercise on this website

http://www.aaaknow.com/rat62ax2.htm

Conclusion

• You can use proportions to help solve a variety of situations

•In collecting data you can find a rule that applies to each situation. Use variables to identify your independent and dependent data

•Your rule should have at least one variable