# Lesson Worksheet: Finding the Area of a Triangle Using Trigonometry Mathematics • 11th Grade

In this worksheet, we will practice finding the area of a triangle using the lengths of two sides and the sine of the included angle.

Q1:

Which of the following is a formula that can be used to find the area of a triangle?

• A
• B
• C
• D
• E

Q2:

In the given figure, work out the area of the triangle to 2 decimal places. Q3:

A small triangular flower bed has measurements as shown in the diagram. Calculate its area in square feet. Give your answer to two decimal places. Q4:

Find the area of an equilateral triangle with a side length of 3 cm, giving the answer in an exact form.

• A cm2
• B cm2
• C cm2
• D cm2
• E9 cm2

Q5:

is a triangle, where , , and . Find the area of , giving your answer to three decimal places.

Q6:

An isosceles triangle has two sides of length 48 cm and base angles of . Find the area of the triangle giving the answer to three decimal places.

Q7:

Find the area of the figure below giving the answer to three decimal places. Q8:

is a parallelogram, where , , and . Find the area of , giving the answer to the nearest square centimeter.

Q9:

is a rhombus with a side length of 24 cm and an interior angle of . Find the area of the rhombus giving the answer to the nearest hundredth.

Q10:

is a triangle where , and the area of the triangle is cm2. Find length giving the answer to two decimal places.