# Expression of a variable from formula - examples - page 17

- Parallelogram

Calculate the missing side of a parallelogram, if you know the perimeter o and one side: a) o = 7.2 cm; b = 1.8 cm b) o = 5.4 cm; a = 1.9 cm - Right triangle eq2

Find the lengths of the sides and the angles in the right triangle. Given area S = 210 and perimeter o = 70. - Coefficient

Determine the coefficient of this sequence: 7.2; 2.4; 0.8 - Inscribed circle

The circle inscribed in a triangle has a radius 3 cm. Express the area of the triangle using a, b, c. - Difference AP 4

Calculate the difference of the AP if a1 = 0.5, a2 + a3 = -1.1 - Volume and area

What is the volume of a cube which has area of 361 cm^{2}? - Combinations

If the number of elements increase by 3, it increases the number of combinations of the second class of these elements 5 times. How many are the elements? - Boys and girls

There are 28 girls in the hall. 5/7 of all children are boys. How many children and how many boys are there? - Trapezium

The area of trapezium is 35 cm^{2}. Find its altitude if the bases are 6cm and 8 cm. - Circle chord

Calculate the length of the chord of the circle with radius r = 10 cm, length of which is equal to the distance from the center of the circle. - The rope

A 68 centimetre long rope is used to make a rhombus on the ground. The distance between a pair of opposite side corners is 16 centimetres what is the distance between the other two corners? - Third member

Determine the third member of the AP if a4=93, d=7.5. - Alley

Alley measured a meters. At the beginning and end are planted poplar. How many we must plant poplars to get the distance between the poplars 15 meters? - Hexagon cut pyramid

Calculate the volume of a regular 6-sided cut pyramid if the bottom edge is 30 cm, the top edge us 12 cm, and the side edge length is 41 cm. - Right triangle from axes

A line segment has its ends on the coordinate axes and forms with them a triangle of area equal to 36 sq. Units . The segment passes through the point ( 5,2). What is the slope of the line segment. ? - Solve equation

solve equation: ? - Free fall

How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss? - Three painters

The three painters have painted bridge. The first would work done in 5 days, the second in 6 days, and the third in 7.5 days. How long will the bridge work if they work together? - Diagonal

he rectangular ABCD trapeze, whose AD arm is perpendicular to the AB and CD bases, has area 15cm square. Bases have lengths AB = 6cm, CD = 4cm. Calculate the length of the AC diagonal. - Area of iso-trap

Find the area of an isosceles trapezoid, if the lengths of its bases are 16 cm, and 30 cm, and the diagonals are perpendicular to each other.

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