a) Corresponding angles of similar figures are congruent, so
![\angle B \cong \boxed{\angle Z}](https://img.qammunity.org/2023/formulas/mathematics/college/jne02spw592yaju34lncd4zbh85229hgsq.png)
b) Scale factor = (image)/(preimage). Since we are looking for ABCD to WZYX, this means that WZYX is the image and ABCD is the preimage. Thus, the scale factor is
![(25)/(10)=\boxed{5/2}](https://img.qammunity.org/2023/formulas/mathematics/college/zxee14c5chw3kbrxl8ue0akvlt0fjfmzo6.png)
c) Since the scale factor is 5/2,
![(20)/(t)=\frac{5}[2}\\\\40=5t\\ \\ t=\boxed{8}](https://img.qammunity.org/2023/formulas/mathematics/college/ub4nxqo4v4380k6x5n8l11o21zaxxn1wow.png)