Area and Perimeter of Triangles

Trigonometric area formula: Area = 1/2 ab sin(C) The area of triangle EFG is 34.8 square units. What is the perimeter of triangle EFG to the nearest unit?

29 units

The area of parallelogram WXYZ is approximately 45 square units. Trigonometric area formula: Area = One-half a b sine (C) What is the approximate perimeter of the parallelogram?

30 units

Lian is making a banner for the school gym. She cut three pieces of fabric into congruent isosceles triangles, as shown. Trigonometric area formula: Area = One-half a b sine (C) To the nearest square inch, how much fabric will she use to make all three triangles?

417 square inches

What is the area of triangle ABC? Round to the nearest tenth of a square unit. Trigonometric area formula: Area =

61.8 square units

An equilateral triangle has a semiperimeter of 6 meters. What is the area of the triangle? Round to the nearest square meter.

7 square meters

Jace ordered a banner in the shape of a parallelogram from a print shop. The print shop charges $1.10 per square foot for banners of any shape and size. What is the approximate cost of the banner before tax?

$92.30

Consider the diagram and the derivation below. Given: In △ABC, AD ⊥ BC Derive a formula for the area of △ABC using angle C. It is given that in △ABC, AD ⊥ BC. Using the definition of sine with angle C in △ACD results in sin(C) =h/b. Using the multiplication property of equality to isolate h, the equation becomes bsin(C) = h. Knowing that the formula for the area of a triangle is A = 1/2 is and using the side lengths as shown in the diagram, which expression represents the area of △ABC?

1/2absin(C)

Trigonometric area formula: Area =1/2absin(C) What is the area of triangle DEF? Round to the nearest tenth of a square unit.

10.3 square units

The perimeter of triangle XYZ is 24 units. What is the area of triangle XYZ? Round to the nearest tenth of a square unit.

14.7 square units

The perimeter of triangle XYZ is 24 units. What is the area of triangle XYZ? Round to the nearest tenth of a square unit. Trigonometric area formula: Area= 1/2 absin(C)

14.7 square units

Lila made a triangular flag to cheer on her favorite sports team. The perimeter of the flag is 20 inches. Approximately how many square inches of fabric were used to make the triangular flag?

15 square inches

What is the area of triangle ABC? Round to the nearest hundredth of a square unit.

81.33 square units

Triangle LMN has sides measuring 7 meters and 6 meters and a perimeter of 16 meters. What is the area of triangle LMN? Round to the nearest square meter.

9 square meters

Triangle ABC is an equilateral triangle with side lengths labeled a, b, and c. Which expressions represent the area of triangle ABC? Select three options.

B, C, E

Which triangle's area can be calculated using the trigonometric area formula?

D

Heron's formula: Area = An equilateral triangle has a semiperimeter of 6 meters. What is the area of the triangle? Round to the nearest square meter.

7 square meters

A spinner for a board game consists of a cardboard circle with two plastic arrows anchored to its center. The arrows are congruent isosceles triangles connected at their bases, as shown. Heron's formula: Area = The base of each triangle measures 2 centimeters and the perimeter of each triangle is 10 centimeters. What is the approximate total area of the plastic triangles on the spinner?

7.7 square centimeters