Answer:

Step-by-step explanation:
1. The measure of an inscribed angle is always half the measure of the arc it forms. Since angle ACB forms arc AB with a measure of 100 degrees, the measure of angle ACB will be equal to
.
2. Relating to problem 1, both inscribed angles marked in the figure form the same arc. All inscribed angles forming the same arc will have the same measure. Therefore, the measure of angle GEF is equal to
.
Answer:
B
Step-by-step explanation:
Let's look at the corresponding ratios:

And we see that the three aren't equal.
Hence, $\Delta ABC$ and $\Delta EDC$ are not similar.
Http://www.pierce.ctc.edu/staff/dlippman/mathinsociety/Finance1.0.pdf I think this will help