At Venn diagram there are 4 parts (20 pieces):
1. Colored only in blue - quadrilaterals with four equal side lengths (3 pieces);
2. Colored only in orange - quadrilaterals with four right angles (6 pieces);
3. Colored in both blue and orange - quadrilaterals with four right angles and with four equal side lengths (2 pieces);
4. Colored in white - quadrilaterals withoutprevious two properties (9 pieces).
Consider events:
A - a randomly chosen quadrilateral has four right angles;
B - a randomly chosen quadrilateral has four equal side lengths;
Use formula to find the probability that a randomly selected quadrilateral with 4 right angles also has four equal side lengths:
Answer: Pr=0.25