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


Mathematical concept/skill options: 
A. Prove and apply trigonometric identities.
B. Model periodic phenomena with trigonometric functions.
C. Interpret functions that arise in applications in terms of the context.
D. Build a function that models a relationship between two quantities.
E. Define, evaluate, and compare functions.
F. Use functions to model relationships between quantities.
G. Understand the concept of a function and use function notation.
H. Analyze functions using different representations.
I. Extend the domain of trigonometric functions using the unit circle.
J. Interpret expressions for functions in terms of the situation they model.
K. Build new functions from existing functions.
L. Construct and compare linear and exponential models and solve problems.


Your response, in json format:
{
  "explanation": "This problem applies trigonometric identities, including the angle addition formula for cosine.",
  "answer": "A"
}

Now, assign the following problem or activity to one or more relevant mathematical concepts/skills it teaches.
shot_info: fl_problem_001894

HS
options: Relate addition and subtraction to length.

Geometric measurement: recognize perimeter as an attribute of plane figures and distinguish between linear and area measures.

Represent and interpret data.

Convert like measurement units within a given measurement system.

Describe and compare measurable attributes.

Geometric measurement: understand concepts of angle and measure angles.

Geometric measurement: understand concepts of volume and relate volume to multiplication and to addition.

Measure and estimate lengths in standard units.

Classify objects and count the number of objects in each category.

Solve problems involving measurement and conversion of measurements from a larger unit to a smaller unit.

Tell and write time.

Geometric measurement: understand concepts of area and relate area to multiplication and to addition.

Measure lengths indirectly and by iterating length units.

Solve problems involving measurement and estimation of intervals of time, liquid volumes, and masses of objects.

Work with time and money.
problem_activity: Narrative
The purpose of this activity is to analyze a clock showing a time when it can be difficult to tell the difference between the hour and the minute hand. This activity allows students to discuss how they know where the hands are placed when the time is to the hour.
Launch
Groups of 2
Display the clock in the first problem.
“Diego and Priya read the clock and got two different times.”
“Who is correct? How do you know?”
Activity
2 minutes: partner discussion
5 minutes: independent work time
Monitor for a student who says the hour hand is pointing to 6 and one who says that for 12:30 the hour hand should be between 12 and 1.
Student Facing
[IMG]
Diego says this clock shows 6:00.
Priya says the clock shows 12:30.
Who do you agree with? Why?
Synthesis:
[IMG]
[IMG]
Student Response
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Activity Synthesis
Invite previously identified students to share.
“Why do you think Priya got mixed up? What could you say to help her revise her thinking?” (Priya mixed up the minute and hour hands. I could remind her that the short hand is the hour and the long hand is the minute. I could remind her that if it was 12:30 the hour hand would have to be between two numbers.)
“On the blank clock, draw hands to show 12:30.”


correct_option_index: 10