The middle line 21 cm long divides this trapezoid into two trapeziums, the middle lines
The middle line 21 cm long divides this trapezoid into two trapeziums, the middle lines of which are 2: 5. find the base of this trapezoid.
Let the length of the middle line HP, trapezium KBCM be equal to 2 * X cm, then, by condition, the length of the middle line LE, trapezium AKMD is equal to 5 * M.
The KM segment is the middle line of the LPRE trapezoid, then:
KM = (HP + LE) / 2.
21 = (2 * X + 5 * X) / 2.
7 * X = 42.
X = 42/7 = 6.
HP = 2 * 6 = 12 cm.
LE = 5 * 6 = 30 cm.
From the KBCM trapezoid, we determine the length of the BC base.
НР = (ВС + КМ) / 2.
12 = (BC + 21) / 2.
BC = 24 – 21 = 3 cm.
From the trapezoid AKMD we determine the length of the base AD.
LE = (CD + KM) / 2.
30 = (CD + 21) / 2.
СD = 60 – 21 = 39 cm.
Answer: The bases of the trapezoid are 3 cm and 39 cm.