Distance B Df
1. **State the problem:** We have rectangle ABDE and parallelogram BCDF. We need to find the perpendicular distance from point B to line DF.
2. **Identify given measurements:**
- BF = 31 cm
- FD = 62 cm (diagonal of parallelogram)
- BD = 64 cm (common side)
3. **Analyze the shapes:**
- Since ABDE is a rectangle, sides AB and DE are perpendicular to BD.
- Parallelogram BCDF shares side BD with the rectangle.
4. **Using properties of parallelogram:** The diagonal FD splits it into two triangles: BFD and CFD.
5. **Find area of triangle BFD using sides BF, BD, and angle:**
We do not have angles directly, so consider using the Law of Cosines in triangle BFD to find angle BFD.
6. **Apply Law of Cosines in triangle BFD:**
$$BD^2 = BF^2 + FD^2 - 2 \cdot BF \cdot FD \cdot \cos(\angle BFD)$$
Plug in values:
$$64^2 = 31^2 + 62^2 - 2 \cdot 31 \cdot 62 \cdot \cos(\angle BFD)$$
$$4096 = 961 + 3844 - 3844 \cdot \cos(\angle BFD)$$
$$4096 = 4805 - 3844 \cdot \cos(\angle BFD)$$
7. **Solve for \(\cos(\angle BFD)\):**
$$3844 \cdot \cos(\angle BFD) = 4805 - 4096 = 709$$
$$\cos(\angle BFD) = \frac{709}{3844} \approx 0.1845$$
8. **Find sine of the angle:**
$$\sin(\angle BFD) = \sqrt{1 - (0.1845)^2} = \sqrt{1 - 0.0340} = \sqrt{0.966} \approx 0.983$$
9. **Calculate area of triangle BFD:**
Area = \(\frac{1}{2} \times BF \times FD \times \sin(\angle BFD)\)
$$= \frac{1}{2} \times 31 \times 62 \times 0.983 \approx 945.9\text{ cm}^2$$
10. **Calculate the height (perpendicular distance) from B to line DF:**
Area = \(\frac{1}{2} \times FD \times \text{height}\)
So,
$$945.9 = \frac{1}{2} \times 62 \times \text{height}$$
$$\text{height} = \frac{2 \times 945.9}{62} = \frac{1891.8}{62} \approx 30.51 \text{ cm}$$
**Final answer:** The perpendicular distance from B to DF is approximately $30.51$ cm.