Lesson 9: Practice Problems

Problem 1

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

A triangle where one angle measures $20^{\circ}$ and another angle measures $45^{\circ}$
A triangle where one angle measures $120^{\circ}$ and another angle measures $50^{\circ}$
A triangle where one angle measures $90^{\circ}$ and another angle measures $100^{\circ}$

Problem 2

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.

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

Problem 3 From Unit 5 Lesson 13

Find a value for $x$ that makes $- x$ less than $2 x$ .
Find a value for $x$ that makes $- x$ greater than $2 x$ .

Problem 4 From Unit 5 Lesson 3

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.

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

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

Problem 5 From Unit 4 Lesson 3

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?