Lesson Notes By Weeks and Term v4 - SHS 1
MEASUREMENT
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MEASUREMENT
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Subject: Mathematics
Class: SHS 1
Term: 2nd Term
Week: 3
Grade code: 1.3.2.LI.2
Strand code: 3
Sub-strand code: 2
Content standard code: 1.3.2.CS.21
Indicator code: 1.3.2.LI.2
Theme: GEOMETRY AROUND US
Subtheme: MEASUREMENT
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In our daily lives in Ghana, we are surrounded by angles and shapes. From the carpenter in Kokomlemle fitting a roof, to the surveyor in the Akuapem hills measuring land, to the artist designing Kente patterns, understanding angles is crucial. Trigonometry is the powerful mathematical tool that connects angles to side lengths in triangles. Today, we will explore some "special" angles that form the foundation of this tool and learn how to find their values, both by hand and with a calculator. This skill is not just for passing exams but for solving real-world problems in construction, engineering, and even navigation for our fishermen at sea.
Part 1: Recap of Basic Trigonometric Ratios (SOH CAH TOA)
Before we look at special angles, let us remember the basic definitions for a right-angled triangle.
Given a right-angled triangle with an angle θ (theta): Opposite (O): The side directly across from the angle θ. Adjacent (A): The side next to the angle θ (that is not the hypotenuse). Hypotenuse (H): The longest side, opposite the right angle.
The three main trigonometric ratios are: Sine: `sin(θ) = Opposite / Hypotenuse` (SOH) Cosine: `cos(θ) = Adjacent / Hypotenuse` (CAH) Tangent: `tan(θ) = Opposite / Adjacent` (TOA)