Area of a circle
Definition: The amount of space inside a circle, measured in square units and found with A = πr².
Example: A circle with a radius of 4 centimeters has an area of about 50.24 square centimeters.
Learn five precise terms for measuring space inside circles and explaining how genetic information helps cells build proteins.
I can use circle-area and genetics vocabulary to calculate measurements and explain how genetic information affects cells, so I can communicate mathematical and scientific reasoning clearly.
✓ I know I am successful when I can define all five terms.
✓ I know I am successful when I can calculate the area of a circle or composite figure and explain the relationship between a gene and a protein.
✓ I know I am successful when I score at least 3 of 4 on the exit check.
Say: “In math, area tells us how much surface a shape covers. In science, genetic information gives cells instructions for carrying out important jobs. Today’s words help us describe both kinds of information precisely.”
Definition: The amount of space inside a circle, measured in square units and found with A = πr².
Example: A circle with a radius of 4 centimeters has an area of about 50.24 square centimeters.
Definition: The constant ratio of a circle’s circumference to its diameter, approximately 3.14.
Example: We use π when calculating a circle’s circumference or area.
Definition: A shape made by combining two or more simple shapes.
Example: A playground formed from a rectangle and a semicircle is a composite figure.
Definition: A segment of DNA containing information a cell uses to make a functional product, often a protein.
Example: A pigment-related gene can provide information used to make a protein involved in flower color.
Definition: A molecule made of amino acids that performs jobs in cells and can influence traits.
Example: Some proteins help produce pigments, while others transport substances or build cell structures.
A circular laboratory dish has a radius of 5 centimeters. Scientists also use a simple model to show how information in DNA can influence an observable trait.
This model is simplified: traits can be influenced by multiple genes, proteins, and environmental factors.
Worked example: A = πr² ≈ 3.14 × 5² = 3.14 × 25 = 78.5 cm². In the science model, the gene contains information the cell uses to make a protein; the protein’s activity can influence a trait.
Choose each answer, check your work, and retry anything you miss.
A biology display is shaped like a 12-foot by 8-foot rectangle with a semicircle on top. The semicircle has a diameter of 8 feet. The display explains how a pigment-related gene provides information used to make a protein involved in purple flower color.
Your task: Find the display’s total area using π ≈ 3.14. Then identify the gene, protein, and resulting trait described in the situation.
Sentence frame: “The rectangle’s area is ___. The semicircle’s area is ___. The total area is ___. The gene contains ___, the protein ___, and the visible trait is ___.”
Your answers stay only on this page.
Practice: 1 π × 6²; 2 circumference-to-diameter ratio; 3 rectangle with two semicircles; 4 segment of DNA containing biological information; 5 molecule that performs jobs in cells.
Application: Rectangle = 96 ft²; semicircle = 25.12 ft²; total = 121.12 ft². The pigment-related gene contains information used to make a pigment-related protein; the protein participates in pigment production; the described visible trait is purple flower color.
Exit: 1 50.24 cm²; 2 30.28 m²; 3 segment of DNA containing information used by a cell; 4 performs a cellular job such as helping produce pigment.