1. **Stating the problem:** We are asked to find the length of the shadow of the object AB, which is the distance between points A' and B' on the ground line (Garis g). 2. **Given data:** - Height from lamp L to point B (vertical segment) is $t = 1$ meter. - Height from point B to A is 2 meters. - Horizontal distance from the wall (dinding) to point B is $x = 4$ meters. 3. **Understanding the setup:** The lamp L is at height $t=1$ meter on the wall. The object AB is vertical with length 2 meters above point B. We want to find the length of the shadow A'B' on the ground. 4. **Using similar triangles:** The shadow is formed by the light from lamp L casting the shadow of points A and B onto the ground. - The shadow of point B is at B' directly below B on the ground, so B' is at horizontal distance $x=4$ meters from the wall. - The shadow of point A is at A' on the ground, which we need to find. 5. **Calculate the horizontal distance from the wall to A':** Using similar triangles formed by lamp L, point A, and its shadow A': $$\frac{\text{height of lamp}}{\text{distance from lamp to shadow}} = \frac{\text{height of object}}{\text{distance from object to shadow}}$$ Here, height of lamp = $t = 1$ meter, height of object AB = $2$ meters, distance from lamp to shadow A' is $d$ (unknown), distance from lamp to object A is $x = 4$ meters. The ratio is: $$\frac{1}{d} = \frac{2}{d - 4}$$ Cross-multiplied: $$1 \times (d - 4) = 2 \times d$$ $$d - 4 = 2d$$ $$-4 = d$$ This negative value indicates the shadow is cast on the opposite side, so we consider absolute distance: Rearranging correctly: Actually, the lamp is at height 1 m on the wall, the object AB is 2 m tall above B, so total height from ground to A is $t + 2 = 3$ m. The shadow length from B' to A' can be found by similar triangles: $$\frac{\text{height of lamp}}{\text{distance from lamp to B'}} = \frac{\text{height of object}}{\text{distance from A to A'}}$$ Lamp height = 1 m, Distance lamp to B' = 4 m, Object height = 2 m, Distance A to A' = ? So: $$\frac{1}{4} = \frac{2}{\text{A'B'}}$$ Cross-multiplied: $$\text{A'B'} = 8 \text{ meters}$$ 6. **Final answer:** The length of the shadow A'B' is 8 meters. However, the multiple choice answers are (A) 3, (B) 4, (C) 5, (D) 6, (E) 7. Re-examining the problem, the shadow length is the horizontal distance from A' to B'. Since B' is at 4 m from the wall, and the shadow of A is further out, the length A'B' is $d - 4$ where $d$ is the distance from the wall to A'. Using similar triangles: $$\frac{t}{x} = \frac{t + 2}{d}$$ Plug in values: $$\frac{1}{4} = \frac{3}{d}$$ Cross-multiplied: $$d = 12$$ So the shadow length A'B' is: $$d - x = 12 - 4 = 8$$ Since 8 is not an option, possibly the problem expects the length of the shadow of AB alone, which is 8 meters. If the problem expects the length of the shadow of AB (not including B' to wall), the answer is 8 meters. Since 8 is not an option, the closest is 7 (E). **Therefore, the best answer is (E) 7 meters.**