Esther drew lines to form triangles and octagons. Esther formed a total of 16 triangles and octagons. She drew 73 more lines for the octagons than for the triangles. How many octagons did she form?
Number of
Octagons |
Lines drawn
for the octagons |
Number of
Triangles |
Lines drawn
for the triangles |
More lines for
the octagons |
16
|
16 x 8 =
128 |
0 |
0 |
128 - 0 =
128 |
| 15 |
15 x 8 =
120 |
1 |
1 x 3 =
3 |
120 - 3 =
117 |
| 11 |
11 x 8 =
88 |
5
|
5 x 3 =
15 |
88 - 15 =
73 |
Number of lines drawn if all the shapes were octagons
= 16 x 8
= 128
Small difference
= 8 + 3
= 11
Big difference
= 128 - 73
= 55
Number of triangles that Esther drew
= 55 ÷ 11
= 5
Number of octagons that Esther drew
= 16 - 5
= 11
Answer(s): 11
