GM5
Right-Angled Triangles
Use Pythagoras and trigonometry to find "invisible" lengths and angles.
Students will discover and apply the rule that for any right-angled triangle, the area of the square on the longest side equals the sum of the areas of the squares on the two shorter sides.
Students will identify the hypotenuse of a right-angled triangle, translate the visual area rule into the algebraic formula $a^2 + b^2 = c^2$, and calculate the length of the hypotenuse.
Students will use Pythagoras' Theorem with subtraction to calculate a shorter side, and write non-whole number answers in exact surd form.
Students will apply the converse of Pythagoras' Theorem to verify whether a given triangle contains a right angle by testing its side lengths.
Students will construct auxiliary lines to reveal hidden right-angled triangles within isosceles triangles, rectangles, trapeziums, and coordinate grids, and apply Pythagoras' Theorem to solve problems.
Students will understand sine, cosine, and tangent as mathematical function machines that take an angle as an input and produce a numerical output, and use a calculator to evaluate direct and inverse trigonometric functions.
Students will correctly label the Opposite, Adjacent, and Hypotenuse sides relative to a reference angle, and discover that the ratio of Opposite divided by Adjacent is constant for any given angle (the Tangent).
Students will utilize the TOA mnemonic and a structured 4-step method to solve for missing side lengths and missing angles using the Tangent ratio.
Students will discover the Sine and Cosine ratios, complete the SOH CAH TOA mnemonic, and use them to calculate missing side lengths and angles.
Students will utilize the "Ticking Method" to accurately and independently select between Sine, Cosine, and Tangent for any given right-angled triangle problem.
Students will connect the Tangent ratio to the gradient of a line, and relate Sine and Cosine to Cartesian coordinates (x, y) using the Unit Circle.
Students will geometrically construct two special triangles to derive the exact fractional and surd values for sine, cosine, and tangent of 30°, 45°, and 60° without a calculator.
Students will independently select between Pythagoras' Theorem and Trigonometry to solve ambiguous geometric diagrams and sequence multiple steps to solve compound shape problems.
Unit code GM5
GM5
Use Pythagoras and trigonometry to find "invisible" lengths and angles.