Trigonometry in Right-Angled Triangles

Rachel explains how to find missing lengths and angles in right-angled triangles using trigonometry. She covers three examples: finding missing side lengths using sine and cosine, and finding a missing angle using tangent. The video emphasizes identifying the hypotenuse, opposite, and adjacent sides, and using trigonometric equations to solve for unknowns. Rachel also provides tips on rearranging equations and using a calculator for accurate results.

What is the acronym used to remember the trigonometric ratios in right-angled triangles?

• TRIGONOMETRY

• SINECOSINE

• Pythagoras

• SOHCAHTOA

Which side is opposite the right angle in a right-angled triangle?

• Base

• Opposite

• Hypotenuse

• Adjacent

If you know the hypotenuse and need to find the opposite side, which trigonometric function should you use?

• Secant

• Cosine

• Tangent

• Sine

What is the value of X if sine 34° = X/12?

• 6.71 cm

• 7.21 cm

• 5.71 cm

• 8.21 cm

Which trigonometric function is used when you have the adjacent side and need to find the hypotenuse?

• Cosecant

• Tangent

• Cosine

• Sine

What is the hypotenuse length if cos 55° = 15/a?

• 26.2 cm

• 15.2 cm

• 20.2 cm

• 30.2 cm

When given the opposite and adjacent sides, which function helps find the angle?

• Sine

• Cosine

• Tangent

• Cotangent

What is the angle B if tan B = 5/8?

• 28.0°

• 32.0°

• 60.0°

• 45.0°

What is the inverse function used to find an angle from a tangent value?

• cos⁻¹

• sin⁻¹

• tan⁻¹

• sec⁻¹

How many significant figures is the angle B rounded to in the example?

• Four

• Three

• Two

• One