帮我讲一下这道题---**Question Stem:** 如图所示，在四边形ABCD中，E, F, G, H分别是四边形ABCD各边的中点，已知阴影部分的面积是20，求四边形SRPQ的面积。 **Translation of Question Stem:** As shown in the figure, in quadrilateral ABCD, E, F, G, H are the midpoints of sides AB, BC, CD, DA respectively. It is known that the area of the shaded parts is 20, find the area of quadrilateral SRPQ. **Other Relevant Text:** Known: Area of shaded parts = 20 Find: Area of quadrilateral SRPQ **Chart/Diagram Description:** * **Type:** Geometric figure (quadrilateral with segments connecting midpoints and diagonals). * **Main Elements:** * **Shape:** A quadrilateral ABCD. * **Points:** Vertices A, B, C, D of the quadrilateral. Points E, F, G, H on the sides AB, BC, CD, DA respectively, indicated as midpoints. Points S, R, P, Q in the interior of the quadrilateral, formed by intersections. * **Lines:** Straight line segments forming the sides AB, BC, CD, DA. Straight line segments connecting midpoints: EG and HF. Straight line segments forming the diagonals: AC and BD. Segments RS, SQ, QP, PR forming the inner quadrilateral SRQP. * **Intersections:** * S is the intersection of EG and AC. * R is the intersection of EG and BD. * Q is the intersection of HF and AC. * P is the intersection of HF and BD. * **Shaded Regions:** Four triangular regions are shaded: triangle AEH, triangle BEF, triangle CFG, and triangle DGH. * **Labels:** Points A, B, C, D, E, F, G, H, S, R, P, Q are labeled. * **Relative Position and Direction:** The figure shows a general convex quadrilateral ABCD. E is on AB, F on BC, G on CD, H on DA. E, F, G, H are midpoints. EG and HF intersect the diagonals AC and BD at points S, R, Q, P forming the inner quadrilateral SRQP. The shaded triangles are formed by the vertices A, B, C, D and the adjacent midpoints. For example, triangle AEH uses vertex A and midpoints E on AB and H on AD. **Options:** No options are provided in the image.