Lesson 9

Use a protractor to try to draw each triangle. Which of these three triangles is impossible to draw?

1. A triangle where one angle measures \(20^\circ\) and another angle measures \(45^\circ\)
2. A triangle where one angle measures \(120^\circ\) and another angle measures \(50^\circ\)

3. A triangle where one angle measures \(90^\circ\) and another angle measures \(100^\circ\)

A triangle has an angle measuring \(90^\circ\), an angle measuring \(20^\circ\), and a side that is 6 units long. The 6-unit side is in between the \(90^\circ\) and \(20^\circ\) angles.

1. Sketch this triangle and label your sketch with the given measures.
2. How many unique triangles can you draw like this?

1. Find a value for \(x\) that makes \(\text-x\) less than \(2x\).
2. Find a value for \(x\) that makes \(\text-x\) greater than \(2x\).

One of the particles in atoms is called an electron. It has a charge of -1. Another particle in atoms is a proton. It has charge of +1.

The overall charge of an atom is the sum of the charges of the electrons and the protons. Here is a list of common elements.

	charge from electrons	charge from protons	overall charge
carbon	-6	+6	0
aluminum	-10	+13
phosphide	-18	+15
iodide	-54	+53
tin	-50	+50

Find the overall charge for the rest of the atoms on the list.

A factory produces 3 bottles of sparkling water for every 7 bottles of plain water. If those are the only two products they produce, what percentage of their production is sparkling water? What percentage is plain?