few_shots: 
Example 1:
Problem/activity:
Find the general solution for:
$${\mathrm{cos}\left({\pi\over2}+x\right)=\mathrm{tan}{\pi\over4}}$$


Concept/skill: 
Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.

Answer: 
No. This problem does not directly teach how side ratios in right triangles lead to definitions of trigonometric ratios. Instead, it involves solving a trigonometric function.

Example 2:
Problem/activity:
Task
Solve the quadratic equation
$$ x^2 = (2x - 9)^2 $$
using as many different methods as possible.


Concept/skill: 
Solve quadratic equations in one variable.

Answer: 
Yes. This task shows one quadratic equation with one variable, x.

Example 3:
Problem/activity:
Task
Suppose $A$ is an angle with vertex $P$, as pictured below:
[IMG]
Draw a circle with center $P$ and with  radius $r \gt 0$.  Explain why the circle
meets each ray of angle $A$ in a single point.  Label these points $Q$ and $R$ respectively.
Draw circles with centers $Q$ and $R$ respectively and radius $r$.  These circles meet at $P$ and a second point to be labelled $B$.
Show that ray $\overrightarrow{PB}$  bisects angle $P$.


Concept/skill: 
Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; copying an angle; bisecting a segment; bisecting an angle; constructing perpendicular lines, including the perpendicular bisector of a line segment; and constructing a line parallel to a given line through a point not on the line.

Answer: 
Yes. This task asks students to draw a ray that bisects an angle. The act of drawing circles and rays may involve compass and straightedge or dynamic geometric software.

Now, does the following problem or activity enable students to learn the full intent of the following concept or skill?

shot_info: fl_problem_001894_neg_0

HS_0

im_task_000870_pos_0

HS_1

im_task_001160_pos_0

HS_2
standard_description: Understand a fraction as a number on the number line; represent fractions on a number line diagram.
Grade 3 expectations in this domain are limited to fractions with denominators 2, 3, 4, 6, and 8.
problem_activity: Narrative
The purpose of this Choral Count is to invite students to practice counting by
\(\frac{1}{2}\)
and notice patterns in the count. These understandings help students develop fluency and will be helpful later in this lesson when students recognize and generate equivalent fractions. In the synthesis, students have the opportunity to notice that
\(\frac{2}{2}\)
and
\(\frac{4}{4}\)
are both equal to 1 whole.
Required Preparation
Have recording of choral count by one-fourth available, from a previous lesson.
Launch
“Count by
\(\frac{1}{2}\)
, starting at
\(\frac{1}{2}\)
.”
Record as students count. Record 2 fractions in each row, then start a new row. There will be 4 rows.
Stop counting and recording at
\(\frac{8}{2}\)
.
Activity
“What patterns do you see?”
1–2 minutes: quiet think time
Record responses.
Student Response
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for free access to Student Response.
Activity Synthesis
Display count by
\(\frac{1}{4}\)
from the previous lesson. There should be 4 rows and 4 fractions in each row with the count ending at
\(\frac{16}{4}\)
.
“How are these two counts the same? How are they different?” (The denominator stays the same in both counts—4 for the last count, and 2 for today’s count. The numerators change in the same way because they both count by one. They start a new line at
\(\frac{2}{2}\)
and
\(\frac{4}{4}\)
, which are both whole numbers.)
Consider asking:
“Who can restate the pattern in different words?”
“Does anyone want to add an observation as to why that pattern is happening here?”
“Do you agree or disagree? Why?”


aligns: no