Posted by **Anonymous** on Tuesday, November 15, 2011 at 10:07pm.

the longer base of an isosceles trapezoid is 14 feet. the nonparallel sides are each 10 feet long and the length of diagonal is 16 feet. find the measure of a base angle

- geometry -
**MathMate**, Tuesday, November 15, 2011 at 10:14pm
So we have a trapezoid ABCD, in which

AB=unknown

BC=10,

CD=14

DA=10

and

AC=16.

Sketch the triangle ACD for which the lengths of all three sides are known.

Using the cosine rule, calculate the cosine of A using

cosA=(AC²+AD²-CD²)/(2*AC*AD)

and hence calculate ∠A.

## Answer This Question

## Related Questions

- geometry - a trapezoid has an area of 5 1/2 feet squared. if the trapezoid has a...
- GEOMETRY - the trapezoid has equal nonparallel sides the upper base is 6. the ...
- geometry - The trapezoid in Exam Figure 6 has equal nonparallel sides. The upper...
- Geometry - The height of the segment from the apex of the pyramid to the base is...
- geometry - Basic Geometry 1. Find the perimeter of a rectangle 19 cm long by 27....
- Geometry - A sandpit in the shape of a rectangular prism has length 7 feet, ...
- geometry - A sandpit in the shape of a rectangular prism has length 7 feet, ...
- Algebra - The cost for paint to cover the exterior of the four sides of a shed ...
- Intro to Algebra - The cost for paint to cover the exterior of the four sides of...
- math - The 2 parallel sides of a trapezoid measure 12 feet and 6 feet. If the ...

More Related Questions