Rappresenta in tre prolezioni ortogonali un dodecagono regolare parallelo al piano yz, inscritto in una circonferenza di centro C (50, 45,40 ) e di raggio 30 il PRIMO passo Il dodecagono è parallelo al piano yz, quindi appa- re nella sua vera forma nella vista da sinistra. Pertanto, dopo aver disegnato le tre proiezioni del centro C, si traccerà il dodecagono nella vista da sinistra.

In the figure below \( P \) and \( Q \) are centres of two circles intersecting at \( A \) and \( B \). The radii are 5 c 8 cm as shown in the diagram. Length of \( A B=8 \mathrm{~cm} \).

6. Two triangles are similar, if one side of the smaller triangle is half of the corresponding side of the larger triangle, and the perimeter of the larger triangle is 52 cm , then what is the perimeter of the smaller triangle?

O4. A stairway 10 ft high is such that cach step accounts for half a foot upward and one foot fonvard. What distance will an ant travel if it starts from ground level to reach the top of the stainay? A) 30 ft B) 33 ft C) 10 ft D) 29 ft

10. ลูกบอลสีมีเส้นผ่านศูนย์กลาง 10 เซนติเมตร มีแถบสีต่างๆ 4 สี แต่ละสีเท่า ๆ กัน แต่ละแถบสีมีพื้นที่เท่าใด (กำหนดให้ \( \pi \approx 3.14 \) )

What do we call the distance around a circle?