few_shots: 
Example 1:
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.

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


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:
Concept/skill: 
Solve quadratic equations in one variable.

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


Answer: 
Yes. This task shows one quadratic equation with 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_neg_0

HS_0

im_task_000870_pos_0

HS_1

im_task_001160_neg_0

HS_2
standard_description: Explain why a fraction a/b is equivalent to a fraction (n × a)/(n × b) by using visual fraction models, with attention to how the number and size of the parts differ even though the two fractions themselves are the same size. Use this principle to recognize and generate equivalent fractions.
Grade 4 expectations in this domain are limited to fractions with denominators 2, 3, 4, 5, 6, 8, 10, 12, and 100.
problem_activity: Problem 1
Would you rather have
$${{4\over9}}$$
,
$${{2\over3}}$$
,
$${{5\over7}}$$
, or
$${{3\over4}}$$
of your favorite pie? Show or explain your reasoning.
Problem 2
Play the following game with a partner using a set of
Fraction Cards
. The goal is to compare the two fractions appearing on each card, determining if they are equivalent and, if not, which is larger. The rules for the game are as follows:
Deal out the cards evenly so that each player has half of the deck. Each player should place their stack face down in front of them.
Each player turns up a card at the same time.
The player with the greater fraction takes both cards and puts them on the bottom of their stack of cards. Students can use any method to compare them. If they disagree, they should discuss until reaching a consensus, drawing a model if necessary.
If the fractions are equivalent, then each player deals three cards facedown and turns the fourth one face up to compare. The player with the larger second fraction takes all of the cards that have been dealt out. If the fractions are again equivalent, then another three are dealt facedown and the fourth face up to be compared. (This can continue as long as it needs to.)
The game is over when one player has all of the cards.


aligns: yes