1. **Problem statement:**
We have a circle with center $C$ and radius 8 cm. The angle $\angle FEG = 45^\circ$ is given.
We need to find:
a. The measure of $\angle FCG$.
b. The length of the chord $FG$ to the nearest tenth of a centimetre.
2. **Understanding the problem and formulas:**
- $C$ is the center of the circle, so $CF$ and $CG$ are radii, each 8 cm.
- $\angle FEG$ is an inscribed angle subtending chord $FG$.
- The central angle $\angle FCG$ subtending the same chord $FG$ is related to the inscribed angle by the rule: the central angle is twice the inscribed angle.
Formula for chord length:
$$ FG = 2r \sin\left(\frac{\theta}{2}\right) $$
where $r$ is the radius and $\theta$ is the central angle in degrees.
3. **Step a: Find $\angle FCG$**
- Since $\angle FEG = 45^\circ$ is an inscribed angle subtending chord $FG$,
- The central angle $\angle FCG$ subtending the same chord is:
$$ \angle FCG = 2 \times \angle FEG = 2 \times 45^\circ = 90^\circ $$
4. **Step b: Find length of chord $FG$**
- Radius $r = 8$ cm
- Central angle $\theta = 90^\circ$
- Using the chord length formula:
$$ FG = 2 \times 8 \times \sin\left(\frac{90^\circ}{2}\right) = 16 \times \sin(45^\circ) $$
- We know $\sin(45^\circ) = \frac{\sqrt{2}}{2} \approx 0.7071$
- So,
$$ FG = 16 \times 0.7071 = 11.3136 \text{ cm} $$
- Rounded to the nearest tenth:
$$ FG \approx 11.3 \text{ cm} $$
**Final answers:**
- a. $\angle FCG = 90^\circ$
- b. Length of chord $FG \approx 11.3$ cm
Circle Angles Chord 455233
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