Answer:
Explanation:
area of bow = area of 2 trapezium + area of rectangle
so, length of rectangle (l) = 6cm
breadth of rectangle (b) = 4cm
therefore, area of rectangle = l×b
= 6×4 cm²
= 24cm²
side a = 10cm
side b = 6cm
and , height of trapezium (h) = 5cm
therefore, area of trapezium = h(a + b) ÷ 2
= 5 ( 6 + 10) ÷ 2
= (5×16) ÷ 2
= 80 ÷ 2
= 40 cm²
area of trapezium = 40cm²
area of both trapeziums are equal as their sides and height are equal
so, area of 2 trapezium = 2 × area of 1 trapezium
= 2 × 40
= 80cm²
therefore, area of bow = area of 2 trapezium + area of rectangle
= 80 + 24
= 104cm²
area of 3 bow = 3 × area of 1 bow
= 3 × 104
= 312cm²
hence, gretchen need 312 square cm of material to construct 3 bows for her sister's doll