tolong jawab no 1-3 yah, pake caranya besok harus di kumpulin. makasih

1. panjang rusuk balok = 4 (p+l+t)
                                      = 4 (80 + 40 + 60)
                                      = 4 x 180
                                      = 720 cm

2. cari dulu panjang diagonal yg lainnya
    1/2D = √13² - 5² = √169 - 25 = √144 = 12
     maka D = 2 x 12 = 24 cm
     Luas alas = 24 x 10 / 2 = 120 cm²
     Volume = 1/3 x Luas alas x tinggi
                  = 1/3 x 120 x 10
                  = 400 cm³

3. Luas permukaan balok = 2 (pl + pt + lt)
                                          = 2 (10 x 8 + 10 x 4 + 8 x 4)
                                          = 2 (80 + 40 + 32)
                                          = 2 x 152
                                          = 304 m²

   Biaya yg dikeluarkan = 304 x Rp. 40.000 = Rp. 12.160.000