# Real World Mathematics

## Math Content: Area and Perimeter Instructional Strategy: Connecting Mathematics to the Real World

Ms. Scott found a way to connect the measurement of perimeter and area to the real world experience as a machining problem that her own father had dealt with in his career as a machinist. Specifically, Ms. Scott describes needing to bore out a hole from a square piece of metal in order to make a certain machine part, such as a type of nut or phlange, and computing the resulting area in order to determine actual amount of material used.

"My father was a Tool and Die Maker for the Boeing Airplane Co. for more than 25 years. While I was in college, I visited him at work one summer. He was "just" a blue collar worker and I was the big math major. But he explained how he did what he did. It was all with trig and real mathematics. He created the parts (the tools) that would make the parts for all of the early airplanes. If you needed a bolt that would screw in 6 inches in 4.5 turns, he would create the tool to create the bolt. Imagine if you can unwind the bolt's threads. He formed a triangle that uses trig to determine the angle of the threads from the length of the shaft and the diameter of the bolt. I suddenly was very impressed with all the real math that my blue collar father knew. Trig is not just for math teachers and mathematicians--but then again, he was a mathematician."

While this real-life example provides a model for a three-dimensional question, the two-dimensional situation described by Ms. Scott was easily visualized by her students using the paper cutout.

In this next clip Ms. Scott supports students in calculating the outside area by using their background knowledge from the rectangle problem. This provides students with scaffolded support to move to their learning to the next level.

Classroom Clip Reflection:

• How does Ms. Scott scaffold instruction for her students?
• What are the implications for your own work with students?