1 / 8

Area of a Triangle 7.3

Area of a Triangle 7.3. JMerrill, 2009. Area of a Triangle (Formula) . When the lengths of 2 sides of a triangle and the measure of the included angle are known, the triangle is uniquely determined. Use: S = ½ ab sin C S = ½ bc sin A S = ½ ac sin B.

xue
Télécharger la présentation

Area of a Triangle 7.3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Area of a Triangle7.3 JMerrill, 2009

  2. Area of a Triangle (Formula) • When the lengths of 2 sides of a triangle and the measure of the included angle are known, the triangle is uniquely determined. Use: • S = ½ ab sin C • S = ½ bc sin A • S = ½ ac sin B Do not memorize all the individual formulas, memorize the pattern: S = ½ (one side)(2nd side)(sine of incl. angle)

  3. Example • Two sides of a triangle have lengths 7cm and 4cm. The angle between the sides measures 73o. Find the area of the triangle. • S = ½ (7)(4)sin 73o • S = 13.388cm2

  4. You Do #1 • Given the triangle ABC with measures of b = 3, c = 8, <A = 120o, find the area: • 10.392units2

  5. Find the area of a regular hexagon inscribed in a unit circle (means the radius is 1 unit). Then approximate the area to 3 significant digits. Example Flashback to geometry…what does “regular” mean? First, divide the hexagon into six congruent triangles.

  6. Second, label the known quantities S=6(½)(1)(1)sin60 S=2.60 units2 Example 1 1 60o Where did the 6 come from?

  7. You Do #2 • Find the area of a regular octagon inscribed in a circle with a radius of 20. Round to the nearest tenth. 1131.4 units2

  8. Approximate the area of the irregularly-shaped piece of land (hint: split it into 2 triangles, one of which is a right triangle). All measurements are given in feet. Round to the nearest whole number. You Do: Challenge 16 110o 5 12 Area of right triangle: 30ft2 Length of drawn segment: 13ft Total area: 101ft2

More Related