Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....

It's always nice to have a plan B. Pupils investigate an alternate formula for the area of a triangle that uses sine. A set of challenge questions shows how the new formula relates to the well-known formula of (1/2)bh.

No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.

Not all triangles are right! Pupils learn to tackle non-right triangles using the Law of Sines and Law of Cosines. After using the two laws, they then apply them to word problems. 

In this math worksheet, students label sides of right triangles as opposite, hypotenuse, and adjacent to the labeled angle. On the second page of the worksheet, students label the part of the right triangle marked with a question mark...

Solving triangles is a breeze. Young boat enthusiasts solve problems involving triangles in the context of sails on a boat. They must apply different strategies, including the Law of Cosines and area formulas.

In this trigonometry worksheet, students solve right triangle problems.  They find the sine, cosine and tangent of given triangles.  This on-line, interactive worksheet contains 6 problems.  Answers are provided.

Learners discover how to find missing sides and angles using trigonometry. Scholars first watch a video covering the Law of Sines and Cosines, as well as the area formula for a triangle. To test their knowledge, they complete a activity...

In this math worksheet, learners are given 7 problems in which they differentiate, figure rate of change, determine value, and prove formulas.

What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...

There isn't a more popular geometry formula than the Pythagorean Theorem! Learners understand the special side relationships in a right triangle. They use the Pythagorean Theorem to find missing sides and to solve problems. They begin...

Students solve problems using sine and cosine. In this precalculus lesson, students apply the properties of sine and cosine to solve non-right triangle problems. They use Heron's Law to find the area of a shape.

Students solve problems using the law of sine and cosine. In this precaclulus lesson, students learn the law of DeMoivre's Theorem and Heron's theorem. They use both theorems to solve problems.

Students solve problems using sine and cosine. For this precalculus lesson, students solve word problems using sine and cosine. They identify where it is appropriate to laws of sine and cosine and where to use the Pythagorean Theorem.

In this trigonometry activity, students solve 15 triangle problems.  Students use the law of sines and law of cosines to find the missing angles and side lengths of a triangles.

For this Archmides' method instructional activity, high schoolers determine the area of a regular n-gon inscribed in a circle.  They use sine and cosine functions to solve problems.  This three-page instructional activity...

Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...

Students define the laws of sine as it relates to a right triangle. In this trigonometry lesson, students identify the properties of sine to help then find mixing sides of a right triangle. They also solve for the missing angles.

Students explore properties of triangles using angle bisectors, incenters, circles, midpoints, and altitudes. They use Geometer's Sketchpad in order to create triangles and their properties.

A basic set-up leads to a surprisingly complex analysis in this variation on the question of surrounding a central circle with a ring of touching circles. Useful for putting trigonometric functions in a physical context, as well as...

In this story problem activity, students read story problems, write equations, and solve. They use the law of sines, the law of cosines, the distance formula, and rates to solve problems. This two-page activity contains seven story...

Tenth graders solve for missing sides on a triangle using the Pythagorean Theorem. In this geometry lesson, 10th graders are introduced to basic trigonometry functions as they solve problems of right triangles. They discuss the...

You'll be spinning in unit circles once you read through this jumbo-sized resource of everything you need to know about trigonometry. Each page has color-coded examples with explicit directions that detail the problems and...

Students make calculations in order to construct a kite in the shape of an isosceles right triangle. In this kite lesson plan students calculate altitude of their flying kites using a formula.