**1. No Quiz about percentage** today

**2. Discount**

- Discount = Marked price – Selling price
- Percentage discount = ( Discount / Marked_price) x 100%
- Selling price = (100% – Discount %) x Marked_price

**3. Sales Tax and Income Tax**

- Tax = Tax_rate x Cost
- Income_tax = Tax_rate x Income
- Income: wage (hourly-paid), salary (annual basis)

**4. Compound Discount**

- Each successive discount is based on the price after the previous discount

**5. Points, Line and Planes**

- Point: has position; has no size
- Line: has an infinite number of points; has no width; can be determined by two points; can be straight or curved
- Ray: a part of a line with one endpoint
- Endpoint
- Line segment: a part of a line between two end points; has length
- Plane: a flat surface; has no thickness
- Parallel lines: two lines on the same plane do not intersect (meet or cut)
- Perpendicular (lines) to each other: two lines intersect at right angle
- Foot of the perpendicular

**6. Types of angles**

- Acute angle: angle < 90 degree
- Right angle: angle = 90 degree
- Obtuse angle: 90 degree < angle < 180 degree
- Reflex angle: 180 degree < angle < 360 degree

**7. Complementary, supplementary, and adjacent angles**

- Complementary angles: the sum of two angles is 90 degree
- Supplementary angles: the sum of two angels is 180 degree
- Adjacent angles: two angles share a common side and a common vertex but do not overlap

**8. Properties of Angles**

- The sum of adjacent angles on a straight line is 180 degree
- The sum of all angles at a point is 360 degree
- Vertically opposite angles: when two lines intersect, the vertically opposite angles are equal

**9. Home Work:**

**Handout:**- Three pages

**Workbook:**- Page 45: 1, 2, 3
- Page 46: 4, 5