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 the leftover king-sized candy bar in Scenario A or Scenario B? The original candy bars were the same size.
{"table": [{"_attributes": {"class": ["table"], "style": "width: 100%;"}, "tbody": [{"tr": [{"td": [{"_attributes": {"style": "text-align: center;"}, "p": [{"_value": "Scenario A"}, {"img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/6IHeGW1e9sEYAohbKOidTN_LVX12G.png"}}]}]}, {"_attributes": {"style": "text-align: center;"}, "p": [{"_value": "Scenario B"}, {"img": [{"_attributes": {"src": "https://d21royfkw9g4l6.cloudfront.net/zmqYDd5fBHecNcxlVQyYLE_C22SZP.png"}}]}]}]}]}]}]}
Problem 2
Find two fractions that are equivalent to each of the following:
a.
$$\frac{1}{3}$$
b.
$$\frac{3}{4}$$
c.
$$\frac{3}{2}$$
Problem 3
Use pictures to explain why the following fractions are equivalent.
a.
$${{1\over2}={3\over6}}$$
b.
$${{2\over3}={8\over12}}$$
c.
$${{4\over3}={8\over6}}$$


aligns: yes