Exercises: Sine, Cosine and Tangent on a right triangle

In a circle with radius $r = 10 c m$ the chord $s$ has the central angle $α = 84^{\circ}$ .

What is the length of the chord?

This content is licensed under
CC BY-SA 4.0 → What does that mean? serlo.org

$\sin (\frac{α}{2})$	$=$	$\frac{x}{r}$
	↓	Solve for $x$ and plug in values.
$x$	$=$	$10 c m \cdot \sin (\frac{84^{\circ}}{2})$
	↓	Compute $x$ .
$x$	$=$	$6.7 c m$
	↓	Since $x$ is half of the chord $s$ , double it to get the chord $s$ .
$s$	$=$	$2 \cdot 6.7 c m$
$s$	$=$	$13.4 c m$