Pie and donut charts in Power BI - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ visualization

intermediate

Choosing the best use case for a pie chart

Which scenario is the best fit for using a pie chart in a Power BI report?

A Displaying sales trends over multiple years for several products.

B Showing the percentage distribution of sales by product category for a single year.

C Comparing the total sales values of different regions using a bar chart.

D Listing detailed sales transactions with customer names and dates.

💡 Hint

Pie charts work best to show parts of a whole at one point in time.

Pie charts are ideal for showing how parts contribute to a whole, such as sales percentages by category in one year. Trends or detailed lists are better shown with other visuals.

❓ dax_lod_result

intermediate

Calculate percentage for pie chart slices

Given a Sales table with columns ProductCategory and SalesAmount, which DAX measure correctly calculates the percentage share of each category for a pie chart?

Power BI

Total Sales = SUM(Sales[SalesAmount])

A Category % = SUM(Sales[SalesAmount]) * 100

B Category % = SUM(Sales[SalesAmount]) / SUM(Sales[SalesAmount])

C Category % = DIVIDE(SUM(Sales[SalesAmount]), CALCULATE(SUM(Sales[SalesAmount]), ALL(Sales[ProductCategory])))

D Category % = CALCULATE(SUM(Sales[SalesAmount]), FILTER(Sales, Sales[ProductCategory] = EARLIER(Sales[ProductCategory])))

💡 Hint

Use DIVIDE and ALL to get total sales ignoring category filter.

Option C divides the sales for the current category by total sales across all categories, correctly calculating the percentage share for pie chart slices.

❓ data_modeling

advanced

Avoiding misleading pie chart slices

You have a pie chart showing sales by region. One region has very low sales, creating a tiny slice hard to see. What is the best data modeling or visualization approach to improve clarity?

A Group small regions into an 'Other' category using a calculated table or grouping feature.

B Remove the small region data from the dataset to simplify the chart.

C Change the pie chart to a donut chart without changing data.

D Increase the font size of the legend to make the small slice label more visible.

💡 Hint

Grouping small slices helps keep charts readable and meaningful.

Grouping small slices into 'Other' consolidates minor categories, making the chart easier to read and interpret without losing data.

🔧 Formula Fix

advanced

Fixing donut chart color mismatch

A donut chart in Power BI shows sales by product category, but the colors in the legend do not match the slices. Which option explains the cause?

A The measure used for values is not numeric, causing color mismatch.

B The data model has duplicate product category names causing color conflicts.

C The donut chart visual does not support legends, so colors are random.

D The chart uses a custom color palette that does not align with the data categories due to manual color assignments.

💡 Hint

Check if colors were manually assigned in the format pane.

Manually assigning colors to categories can cause mismatches if the order or categories change. Using consistent automatic colors avoids this issue.

🧠 Conceptual

expert

Limitations of pie and donut charts in BI dashboards

Which statement best describes a key limitation of pie and donut charts in business intelligence dashboards?

A They are ineffective for comparing many categories because small slices become hard to distinguish.

B They cannot display percentage values and require additional calculations.

C They always require 3D effects to be visually appealing and clear.

D They automatically update with real-time data without any configuration.

💡 Hint

Think about how many slices a pie chart can show clearly.

Pie and donut charts work best with few categories. Many small slices make it difficult to compare and interpret data accurately.