Ho fumana pherimitha ea trapezoid: foromo le mesebetsi

Khatisong ena, re tla tšohla mokhoa oa ho bala pherimitha ea trapezoid le ho sekaseka mehlala ea ho rarolla mathata.

Foromo ea potoloho

Pherimitha (P) ea trapezoid e lekana le kakaretso ea bolelele ba mahlakore ohle a eona.

P = a + b + c + d

• b и d - motheo oa trapezoid;
• a и с – mahlakore a eona.

Pherimitha ea isosceles trapezoid

Ho trapezoid ea isosceles, mahlakore a lekana (a uXNUMXd c), ke ka lebaka leo e bitsoang isosceles. Perimeter e baloa ka tsela ena:

P = 2a + b + d or P = 2s + b + d

Pherimitha ea trapezoid e khutlonnetsepa

Ho bala perimeter, ho sebelisoa mokhoa o tšoanang le oa scalene trapezoid.

P = a + b + c + d

Mehlala ea mesebetsi

Mosebetsi 1

Fumana pherimitha ea trapezoid haeba metheo ea eona e le 7 cm le 10 cm le mahlakore a eona a 4 cm le 5 cm.

Qeto:

Re sebelisa mokhoa o tloaelehileng, ho nkela bolelele ba mahlakoreng a tsejoang ho eona: P u7d 10 cm + 4 cm + 5 cm + 26 cm uXNUMXd XNUMX cm.

Mosebetsi 2

Sebaka se pakeng tsa isosceles trapezoid ke 22 cm. Fumana bolelele ba lehlakore haeba metheo ea setšoantšo e le 3 cm le 9 cm.

Qeto:

Joalo ka ha re tseba, pherimitha ea isosceles trapezoid e baloa ka foromo: P = 2a + b + dWhere а – lehlakore.

Bolelele ba eona bo atolositsoeng ka bobeli ke: 2a = P - b - d = 22 cm - 3 cm - 9 cm = 10 cm.

Ka hona, bolelele ba lehlakore ke: a = 10 cm / 2 = 5 cm.