# Triangle - 9th grade (14y) - examples

- Regular quadrangular pyramid

The height of the regular quadrangular pyramid is 6 cm, the length of the base is 4 cm. What is the angle between the ABV and BCV planes? - A boy

A boy of height 1.7m is standing 30m away from flag staff on the same level ground . He observes that the angle of deviation of the top of flag staff is 30 degree. Calculate the height of flag staff. - Right angled triangle 3

Side b = 1.5, hypotenuse angle A = 70 degrees, Angle B = 20 degrees - A bridge

A bridge over a river is in the shape of the arc of a circle with each base of the bridge at the river's edge. At the center of the river, the bridge is 10 feet above the water. At 27 feet from the edge of the river, the bridge is 9 feet above the water. H - Equilateral triangle

Calculate the area of an equilateral triangle with circumference 72cm. - Equilateral triangle

A square is inscribed into an equilateral triangle with a side of 10 cm. Calculate the length of the square side. - Ruler and compass

Use a ruler and compass to construct a triangle ABC with AB 5cm BAC 60° and ACB 45°. - Coordinate axes

Determine the area of the triangle given by line -7x+7y+63=0 and coordinate axes x and y. - Garden

Area of square garden is 4/5 of triangle garden with sides 24 m, 15 m and 15 m. How many meters of fencing need to fence a square garden? - Trapezoid MO

The rectangular trapezoid ABCD with right angle at point B, |AC| = 12, |CD| = 8, diagonals are perpendicular to each other. Calculate the perimeter and area of the trapezoid. - Right Δ

Right triangle has length of one leg 51 cm and length of the hypotenuse 85 cm. Calculate the height of the triangle. - Axial section

Axial section of the cone is equilateral triangle with area 208 dm^{2.}Calculate volume of the cone. - Circle chord

What is the length d of the chord circle of diameter 36 m, if distance from the center circle is 16 m? - Trigonometric functions

In right triangle is: ? Determine the value of s and c: ? ? - Rectangle

The rectangle is 31 cm long and 28 cm wide. Determine the radius of the circle circumscribing rectangle. - Triangle SAS

Calculate area and perimeter of the triangle, if the two sides are 51 cm and 110 cm long and angle them clamped is 130°. - Gimli Glider

Aircraft Boeing 767 lose both engines at 45000 feet. The plane captain maintain optimum gliding conditions. Every minute, lose 1870 feet and maintain constant speed 212 knots. Calculate how long takes to plane from engines failure to hit ground. Calculate - Short cut

Imagine that you are going to the friend. That path has a length 270 meters. Then turn left and go another 1810 meters and you are at a friend's. The question is how much the journey will be shorter if you go direct across the field? - River

From the observatory 14 m high and 32 m from the river bank, river width appears in the visual angle φ = 20°. Calculate width of the river. - Regular 5-gon

Calculate area of the regular pentagon with side 7 cm.

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See also our trigonometric triangle calculator. See also more information on Wikipedia.