1. **Problem statement:** Given a circular body with intersecting chords in a quadrilateral shape, with points A, B, C, D, and E inside the figure. Given: $AC = 118.7$ m. We need to calculate $\sin ACD$, $\cos ACD$, and $\tan ACD$. Then calculate the chord $EC$ by two different methods. Finally, calculate the perimeter of the light source by converting to unit length. 2. **Formulas and rules:** - For angle $ACD$, use the triangle $ACD$. - $\sin \theta = \frac{\text{opposite side}}{\text{hypotenuse}}$ - $\cos \theta = \frac{\text{adjacent side}}{\text{hypotenuse}}$ - $\tan \theta = \frac{\text{opposite side}}{\text{adjacent side}}$ - Use Pythagoras theorem for chord lengths. 3. **Calculations for $\sin ACD$, $\cos ACD$, $\tan ACD$:** Assuming $ACD$ is a triangle with $AC=118.7$ m. We need lengths of sides $AD$ and $CD$ or their projections. 4. **Calculate chord $EC$ by two methods:** - Method 1: Using triangle properties and intersecting chords theorem. - Method 2: Using circle properties and segment lengths. 5. **Calculate perimeter of the light source:** - The shape is a rectangle with semicircles at ends. - Perimeter $= 2 \times$ rectangle length $+ 2 \times$ semicircle circumference. - Semicircle circumference $= \pi \times$ diameter. 6. **Final answers:** - $\sin ACD$, $\cos ACD$, $\tan ACD$ values depend on given or derived side lengths. - $EC$ length calculated by both methods. - Perimeter calculated as described. Since exact side lengths for $AD$, $CD$, and $EC$ are not fully provided, the problem requires additional data for numeric answers. **Slug:** circular chords **Subject:** geometry