few_shots: 
Example 1:
Concept/skill: 
Prove the addition and subtraction formulas for sine, cosine, and tangent and use them to solve problems.

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


Answer: 
Yes. An initial step when solving for x in this problem requires the use of the addition formula for cosine on the left side of the equation.

Example 2:
Concept/skill: 
Understand that the graph of an equation in two variables is the set of all its solutions plotted in the coordinate plane, often forming a curve (which could be a line).

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


Answer: 
No. This task does not involve an equation in two variables. There is only one variable, x.

Example 3:
Concept/skill: 
Construct a tangent line from a point outside a given circle to the circle.

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 $P$.


Answer: 
No. This task does not involve drawing lines that are tangent to circles. The only line that may be drawn is the ray between points P and B.

Now, assess whether the following problem or activity is 'aligned' with the given Common Core standard in Mathematics.

shot_info: fl_problem_001894_pos_0

HS_0

im_task_000870_neg_0

HS_1

im_task_001160_neg_0

HS_2
standard_description: Partition circles and rectangles into two and four equal shares, describe the shares using the words halves, fourths, and quarters, and use the phrases half of, fourth of, and quarter of. Describe the whole as two of, or four of the shares. Understand for these examples that decomposing into more equal shares creates smaller shares.
problem_activity: Narrative
The purpose of this activity is for students to match language to visual representations of rectangles and circles
partitioned and shaded in different ways.
Representation: Access for Perception.
Read each of the phrases aloud. Students who both listen to and read the information will benefit from extra processing time.
Supports accessibility for: Language, Conceptual Processing
Launch
Groups of 2
Activity
Read the task statement.
“You may use the phrases more than once.”
6 minutes: partner work time
Student Facing
Here are some ways to describe the shapes.
split into fourths
split into halves
split into quarters
a half shaded
a quarter shaded
a fourth shaded
two of the halves shaded
four of the fourths shaded
Label each shape with at least one phrase from the lists.
[IMG]
[IMG]
[IMG]
[IMG]
[IMG]
[IMG]
[IMG]
Student Response
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Activity Synthesis
Display the circle with four of the fourths shaded.
“Let’s list all the ways we could describe this shape.” (It’s split into fourths. It is split into quarters. Four of the fourths are shaded.)
Repeat with other shapes as time permits.


aligns: yes