MEASUREMENTS

Surface Area of Triangular and Rectangular-Based Prisms

By the end of the lesson, the learner should be able to:

-Draw a triangular prism and identify its faces, edges, and vertices;
-Develop a net for a triangular prism;
-Calculate the surface area of a triangular prism using its net;
-Appreciate the practical applications of surface area calculations.

In groups, learners are guided to:
-Collect from the environment objects that are triangular prisms;
-Draw and sketch nets of triangular prisms;
-Measure dimensions of the faces on the nets;
-Calculate the area of each face and add to find the total surface area;
-Discuss and share results with other groups.

How do we determine the surface area of a triangular prism?

-Mathematics learners book grade 9 page 94;
-Manila paper for making nets;
-Scissors;
-Rulers;
-Objects with triangular prism shapes;
-Glue.
-Mathematics learners book grade 9 page 95;
-Objects with rectangular prism shapes (boxes);

-Observation of practical work; -Oral questions; -Written exercises; -Group work assessment.

MEASUREMENTS

Surface Area of Triangular, Rectangular and Square-Based Pyramids

By the end of the lesson, the learner should be able to:

-Draw a triangular-based pyramid and identify its faces, edges, and vertices;
-Develop a net for a triangular-based pyramid;
-Calculate the surface area of a triangular-based pyramid;
-Develop interest in calculating surface areas of pyramids.

In groups, learners are guided to:
-Collect objects shaped like triangular-based pyramids;
-Draw and sketch nets of triangular-based pyramids;
-Measure dimensions of the faces on the nets;
-Calculate the area of each face and add to find the total surface area;
-Discuss and share results with other groups.

How do we determine the surface area of a triangular-based pyramid?

-Mathematics learners book grade 9 page 96;
-Manila paper for making nets;
-Scissors;
-Rulers;
-Objects with triangular pyramid shapes;
-Glue.
-Mathematics learners book grade 9 page 97;
-Objects with rectangular pyramid shapes;

-Observation of practical work; -Oral questions; -Written exercises; -Model making assessment.

MEASUREMENTS

Surface Area of a Cone in Real Life Situations

By the end of the lesson, the learner should be able to:

-Identify and draw a cone;
-Develop a net for a cone;
-Identify the parts of a cone (base, curved surface, apex, slant height);
-Show interest in relating cones to real-life objects.

In groups, learners are guided to:
-Collect objects with conical shapes;
-Draw and discuss features of cones;
-Draw circles and cut out sectors to form cone nets;
-Fold sectors to form cones and observe the relationship between the sector angle and the cone dimensions;
-Discuss and share findings with other groups.

What are some real-life objects that have a conical shape?

-Mathematics learners book grade 9 page 102;
-Circular paper cut-outs;
-Scissors;
-Rulers;
-Protractors;
-Conical objects (funnels, party hats);
-Glue.
-Mathematics learners book grade 9 page 103;
-Cone models;
-Scientific calculators;
-Charts showing formulas for surface area of cones.

-Observation of practical work; -Oral questions; -Model making assessment; -Group presentations.

MEASUREMENTS

Surface Area of a Sphere in Real Life Situations

By the end of the lesson, the learner should be able to:

-Identify and draw a sphere;
-Identify spherical objects in the environment;
-Calculate the surface area of a sphere using the formula A = 4πr²;
-Develop interest in calculating surface area of spheres.

In groups, learners are guided to:
-Collect objects with spherical shapes;
-Measure the diameter/radius of spherical objects;
-Calculate the surface area of spheres using the formula A = 4πr²;
-Discuss and share findings with other groups;
-Relate surface area of spheres to real-life applications.

What are some real-life objects that have a spherical shape?

-Mathematics learners book grade 9 page 104;
-Spherical objects (balls, oranges);
-Measuring tape/rulers;
-Scientific calculators;
-Charts showing formulas for surface area of spheres.

-Observation; -Oral questions; -Written exercises; -Group presentations.